You may want to install a tool like "codec sniper" -- something that will list all of your codecs, tell you if they are "ok" or "broken", and let you remove bad codecs.
Just Google "codec sniper".
Also, don't use "full frames (uncompressed)" unless you really need to. I suggest either the "Lagarith" or "Huffy UV" codecs instead. They're lossless, both support alpha, and will give you MUCH smaller file sizes than uncompressed.
Alan.
http://www.wondertouch.com