array error

Since installing a new theme, I am getting the following error on all my blogs (yay me!)
Warning: array_merge() [function.array-merge]: Argument #2 is not an array in /mounted-storage/home86b/sub008/sc47150-SGYS/airsoftsite.info/wp-includes/widgets.php on line 53

To make things extra special it is stopping the bringing up of the wp-admin pages or login pages to get in and change back themes.

An example can be seen at http://www.burnsite.info

Cheers