xmbc video nolonger works

Using the video plugins it works when I switched accidentally switched from Perian h264 from Apple h264 (of course, youtube outside xbmc didn’t work) Once I went back to the Apple h264 by copying it back to the right directory, videos doesn’t work in XBMC for youtube and others. It loads the directory and goes right back to the interface. The video never plays. It works in Boxee just fine

Apple trails doesn’t work either.

I does work, for example, with the NBC Universal. eg, I just randomly choose 30 rock and it worked. Any ideas?

today I updated to 3.6.3, nothing. Perian is installed, mplayer codecs are up to date, Smart Installer just ran?

Sometimes i get the error playlist playback aborted too many consecutive items failed.