Hi Tim,
You headed me to the answer by referring to the SimConnect file location. I had placed it in Program Data\Microsoft\FSX not ..........AppData\Roaming\Microsoft\FSX. Once in this latter file with the Plan G connection set for IPv6 it worked immediately. No wonder nearly all the books in my library have titles ending in "....................for Dummies".
A fantastic piece of FSX software and superlative service.
Thank you,
John

Hi Tim,
Thank you for the prompt response; the delay on my part is I am corresponding from Brisbane.
I can confirm both computers have permanent IP configs. (FSX 192.168.0.8 and Plan G 192.168.0.6) Here are the files written for xml in both IPv4 & IPv6:
SimConnect IPv4

<?xml version="1.0" encoding="Windows-1252"?>
<SimBase.Document Type="SimConnect" version="1,0">
<Descr>SimConnect</Descr>
<Filename>SimConnect.xml</Filename>
<SimConnect.Comm>
<Disabled>False</Disabled>
<Protocol>IPv4</Protocol>
<Scope>global</Scope>
<Address>192.168.0.8</Address>
<MaxClients>64</MaxClients>
<Port>4506</Port>
<MaxRecvSize>4096</MaxRecvSize>
<DisableNagle>False</DisableNagle>
</SimConnect.Comm>
</SimBase.Document>

SimConnect IPv6

<?xml version="1.0" encoding="Windows-1252"?>
<SimBase.Document Type="SimConnect" version="1,0">
<Descr>SimConnect</Descr>
<Filename>SimConnect.xml</Filename>
<SimConnect.Comm> <Disabled>False</Disabled>
<Protocol>IPv6</Protocol>
<Scope>link-local</Scope>
<MaxClients>64</MaxClients>
<Address>fe80::84fc:e223:677:4f13</Address>
<Port>4506</Port>
</SimConnect.Comm>
</SimBase.Document>

I have used different port addresses as per manual between 4501 and 4509 but still get the same result.
Previously I used Plan G on a the single FSX computer successfully before having a new build for FSX and deciding to network it to the old desktop. (I still have FSX on the old unit, would that make any difference?)
Thanks for a great programme.
Jaycem

Hi,
Have been trying to connect between two Desktops on Windows 7. Have followed manual instructions in variety of attempts to no avail. Tried altering the Ports but still crashes after trying to connect.
here is the Plan G Log for today:
13:59:00.9 Starting Plan-G (W7 edition), build 3.1.2.101
13:59:00.9 OS is Microsoft Windows NT 6.1.7601 Service Pack 1
13:59:01.4 InitDataFolder
13:59:01.4 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FSX.sdf
13:59:01.4 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FS9.sdf
13:59:01.4 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_XPX.sdf
13:59:01.4 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_P3D.sdf
13:59:01.4 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_NAVI.sdf
13:59:01.4 Data Source = C:\Users\John\Documents\Plan-G Files\Data\UserWaypoints.sdf
13:59:01.4 Data Source = C:\Users\John\Documents\Plan-G Files\Data\MEF.sdf
13:59:02.2 Map tiles cache: C:\Users\John\AppData\Local\GMap.NET\
13:59:02.5 Program in: C:\Program Files (x86)\Plan-G v3.1.2
13:59:02.5 Data in: C:\Users\John\Documents\Plan-G Files
13:59:02.5 IsDataLoaded: FSX
13:59:02.5 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FSX.sdf
13:59:04.5 This build: 312101 Latest build: 312101
13:59:04.5 Starting timer
13:59:04.5 DownloadCurrentMetars thread started
13:59:04.5 sTAF00Z.TXT started
13:59:04.5 Metar02Z.TXT started
13:59:04.5 Metar03Z.TXT started
13:59:04.5 lTAF18Z.TXT started
13:59:04.5 sTAF18Z.TXT started
13:59:04.5 lTAF00Z.TXT started
13:59:04.9 IsDataLoaded: FSX
13:59:04.9 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FSX.sdf
13:59:04.9 IsDataLoaded: FS9
13:59:04.9 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FS9.sdf
13:59:04.9 IsDataLoaded: P3D
13:59:04.9 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_P3D.sdf
13:59:04.9 IsDataLoaded: XPlane
13:59:04.9 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_XPX.sdf
13:59:05.4 sTAF18Z.TXT done
13:59:06.1 sTAF00Z.TXT done
13:59:06.7 lTAF18Z.TXT done
13:59:07.0 Stopping timer
13:59:07.0 StartMap
13:59:07.0 Connection string: metadata=res://*/Data.FSData.csdl|res://*/Data.FSData.ssdl|res://*/Data.FSData.msl;provider=System.Data.SqlServerCe.3.5;provider connection string='Data Source=|DataDirectory|\Data\PlanG3_FSX.sdf'
13:59:07.7 NdbsInBounds 3
13:59:07.8 VorsInBounds 3
13:59:08.1 AirportsInBounds 19
13:59:08.6 AirspaceInBounds 55
13:59:08.7 NdbsInBounds 3
13:59:08.7 VorsInBounds 3
13:59:08.7 AirportsInBounds 19
13:59:08.8 AirspaceInBounds 55
13:59:10.1 _Backstage_IsOpenChanged: True
13:59:15.1 lTAF00Z.TXT done
13:59:17.9 Metar03Z.TXT done
13:59:20.2 Metar02Z.TXT done
13:59:20.2 DownloadCurrentMetars done
13:59:20.9 ProcessMetars done
13:59:53.6 _Backstage_IsOpenChanged: False
14:00:13.2 NdbsInBounds 3
14:00:13.2 VorsInBounds 3
14:00:13.2 AirportsInBounds 19
14:00:13.4 AirspaceInBounds 56
14:04:55.0 Initiating SimConnect connection.
14:04:55.0 Connect
14:04:55.0 SimConnect.Connect - Remote. Mode = IPv4 Server = 192.168.0.8 Port = 4507
14:05:00.3 SimConnect connection attempt timed out
14:05:00.3 Disconnect
14:05:01.3 Disconnected from sim
14:55:39.4

---===+++===---

14:55:39.4 Starting Plan-G (W7 edition), build 3.1.2.101
14:55:39.4 OS is Microsoft Windows NT 6.1.7601 Service Pack 1
14:55:39.6 InitDataFolder
14:55:39.6 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FSX.sdf
14:55:39.6 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FS9.sdf
14:55:39.6 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_XPX.sdf
14:55:39.6 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_P3D.sdf
14:55:39.6 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_NAVI.sdf
14:55:39.6 Data Source = C:\Users\John\Documents\Plan-G Files\Data\UserWaypoints.sdf
14:55:39.6 Data Source = C:\Users\John\Documents\Plan-G Files\Data\MEF.sdf
14:55:40.2 Map tiles cache: C:\Users\John\AppData\Local\GMap.NET\
14:55:40.5 Program in: C:\Program Files (x86)\Plan-G v3.1.2
14:55:40.5 Data in: C:\Users\John\Documents\Plan-G Files
14:55:40.5 IsDataLoaded: FSX
14:55:40.5 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FSX.sdf
14:55:41.1 This build: 312101 Latest build: 312101
14:55:41.1 Starting timer
14:55:41.1 DownloadCurrentMetars thread started
14:55:41.1 Metar03Z.TXT started
14:55:41.2 Metar04Z.TXT started
14:55:41.2 lTAF18Z.TXT started
14:55:41.2 sTAF00Z.TXT started
14:55:41.2 lTAF00Z.TXT started
14:55:41.2 sTAF18Z.TXT started
14:55:41.4 IsDataLoaded: FSX
14:55:41.5 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FSX.sdf
14:55:41.5 IsDataLoaded: FS9
14:55:41.5 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_FS9.sdf
14:55:41.5 IsDataLoaded: P3D
14:55:41.5 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_P3D.sdf
14:55:41.5 IsDataLoaded: XPlane
14:55:41.5 Data Source = C:\Users\John\Documents\Plan-G Files\Data\PlanG3_XPX.sdf
14:55:42.2 sTAF18Z.TXT done
14:55:43.0 sTAF00Z.TXT done
14:55:43.7 Stopping timer
14:55:43.7 StartMap
14:55:43.7 Connection string: metadata=res://*/Data.FSData.csdl|res://*/Data.FSData.ssdl|res://*/Data.FSData.msl;provider=System.Data.SqlServerCe.3.5;provider connection string='Data Source=|DataDirectory|\Data\PlanG3_FSX.sdf'
14:55:44.2 NdbsInBounds 3
14:55:44.3 VorsInBounds 3
14:55:44.5 AirportsInBounds 19
14:55:44.8 AirspaceInBounds 55
14:55:44.8 NdbsInBounds 3
14:55:44.9 VorsInBounds 3
14:55:44.9 AirportsInBounds 19
14:55:45.0 AirspaceInBounds 55
14:55:45.2 Initiating SimConnect connection.
14:55:45.2 Connect
14:55:45.2 SimConnect.Connect - Remote. Mode = IPv4 Server = localhost Port = 0
14:55:45.2 Connect: BeatlesBlog.SimConnect.SimConnect+SimConnectException: Open: iPort value is invalid
   at BeatlesBlog.SimConnect.SimConnect.Open(String strAppName, String strHostName, Int32 iPort, Boolean bIsIPV6)
   at Plan_G3.Model.SIMCONNECT.Connect()
14:55:45.2 SimConnect connection failed.
14:55:45.2 Disconnect
14:55:45.2 Disconnected from sim
14:55:49.2 Initiating SimConnect connection.
14:55:49.2 Connect
14:55:49.2 SimConnect.Connect - Remote. Mode = IPv4 Server = localhost Port = 0
14:55:49.2 Connect: BeatlesBlog.SimConnect.SimConnect+SimConnectException: Open: iPort value is invalid
   at BeatlesBlog.SimConnect.SimConnect.Open(String strAppName, String strHostName, Int32 iPort, Boolean bIsIPV6)
   at Plan_G3.Model.SIMCONNECT.Connect()
14:55:49.2 SimConnect connection failed.
14:55:49.2 Disconnect
14:55:49.2 Disconnected from sim
14:55:49.5 lTAF18Z.TXT done
14:55:49.7 lTAF00Z.TXT done
14:56:10.3 Initiating SimConnect connection.
14:56:10.3 Connect
14:56:10.4 SimConnect.Connect - Remote. Mode = IPv4 Server = localhost Port = 0
14:56:10.4 Connect: BeatlesBlog.SimConnect.SimConnect+SimConnectException: Open: iPort value is invalid
   at BeatlesBlog.SimConnect.SimConnect.Open(String strAppName, String strHostName, Int32 iPort, Boolean bIsIPV6)
   at Plan_G3.Model.SIMCONNECT.Connect()
14:56:10.4 SimConnect connection failed.
14:56:10.4 Disconnect
14:56:10.4 Disconnected from sim
14:56:13.9 Initiating SimConnect connection.
14:56:13.9 Connect
14:56:13.9 SimConnect.Connect - Remote. Mode = IPv4 Server = localhost Port = 0
14:56:13.9 Connect: BeatlesBlog.SimConnect.SimConnect+SimConnectException: Open: iPort value is invalid
   at BeatlesBlog.SimConnect.SimConnect.Open(String strAppName, String strHostName, Int32 iPort, Boolean bIsIPV6)
   at Plan_G3.Model.SIMCONNECT.Connect()
14:56:13.9 SimConnect connection failed.
14:56:13.9 Disconnect
14:56:13.9 Disconnected from sim
14:56:15.6 _Backstage_IsOpenChanged: True
14:56:54.0 Metar04Z.TXT done
14:57:35.3 Metar03Z.TXT done
14:57:35.3 DownloadCurrentMetars done
14:57:36.0 ProcessMetars done
14:58:36.2 _Backstage_IsOpenChanged: False
14:58:38.6 Initiating SimConnect connection.
14:58:38.6 Connect
14:58:38.6 SimConnect.Connect - Remote. Mode = IPv6 Server = fe80::84fe:e223:677:4f13 Port = 4508
14:58:43.6 SimConnect connection attempt timed out
14:58:43.6 Disconnect
14:58:44.6 Disconnected from sim

Here is the Windows Log:
Problem signature:
  Problem Event Name:   CLR20r3
  Problem Signature 01:   Plan-G3.exe
  Problem Signature 02:   3.1.2.101
  Problem Signature 03:   54aaa0ff
  Problem Signature 04:   BeatlesBlog.SimConnect
  Problem Signature 05:   0.1.1.0
  Problem Signature 06:   4a593cba
  Problem Signature 07:   65
  Problem Signature 08:   6f
  Problem Signature 09:   System.NullReferenceException
  OS Version:   6.1.7601.2.1.0.768.3
  Locale ID:   1033
  Additional Information 1:   0a9e
  Additional Information 2:   0a9e372d3b4ad19135b953a78882e789
  Additional Information 3:   0a9e
  Additional Information 4:   0a9e372d3b4ad19135b953a78882e789

Can anyone help or offer advice?
Many thanks
Jaycem