These warnings were likely there also before the vBulletin upgrade, but there is a 4.2.2 change in the error handler which will force php to display errors even if you have set them to off in your php.ini.
--------------- Added [DATE]1381359117[/DATE] at [TIME]1381359117[/TIME] ---------------
The fix is listed at vbulletin.com:
http://www.vbulletin.com/forum/forum...-been-released