Hi, I'm trying to download plan G but every single download link I find goes to an error

The error usually says "Parse error: syntax error, unexpected '::' (T_PAAMAYIM_NEKUDOTAYIM) in /home3/timarnot/public_html/tasoftware.co.uk/blog/wp-content/plugins/download-manager/libs/class.CategoryHandler.php on line 299"

Anything I can try?