Using this:
https://vborg.vbsupport.ru/attachmen...6&d=1335142146
and doing the change of "=&" to "=" (2 changes) in it fixed my install on 4.2.1
i also did the =& swap in the arcade.php in my admincp folder.

RESULT! :up:
Edit: then i was unable to start the arcade page from navigation in VBa, got "invalid Redirect URL" errors after being asked to log in, even though
i was logged in.. stopped using the Vba link, instead used the Navigation manager to link to it.. fixed it.
Now i have the issue with getting redirected to the 'activity stream' after a game
EDIT: Fixed it: needs edit to index.php _also_ in my FORUM folder, as i'm using vbadvanced, (see here:
https://vborg.vbsupport.ru/showthread.php?t=279298 ) i also made the .htaccess edit in my site root, not sure
if this matters. now all is good