Cannot use a scalar value as an array in Callbacks.inc on line 65

My server log is full of this error
"Cannot use a scalar value as an array in /var/www/html/gallery2/modules/core/Callbacks.inc on line 65"

Just by doing a google search, there are three other sites i have found with the same error and they obviously have their debug mode on i guess.

http://www.deftz.de/picstore/gallery-2.2-rc-2/main.php?g2_itemId=917
http://www.apisupport.com/gallery2/main.php?g2_itemId=477
http://martins-fotopage.de/v/west_highland_way/drumquhassle-rowardennan/DSCN1384.jpg.html

Doesn't anybody know how to fix this? i only got it after switching to the extreme theme,
so i don't consider modifying the gallery core files to be a valid solution unless the mod is posted by the gallery2 team.

I am using X_treme theme on gallery 2.2 latest release.