Once having configured K2 to my needs (cats, Items etc...) on my local server (AMPSS on a MacbookPro OSX Lion) I set-up the menus and sub-menus I wanted and now the site crashes with this error message:

Catchable fatal error: Object of class __PHP_Incomplete_Class could not be converted to string in /Applications/AMPPS/www/donalek01/plugins/system/debug/debug.php on line 303

Any idea of how I could recuperate my site?

Thank you very much.

I disabled all K2 extensions, rebooted (the Mac, AMPS), then enabled K2 again and the site worked again.
I'm glad but a bit concerned that it happens when "live". All the apps ar up to date.
Thanks