Cell phone video is very hard to edit... you don't state your brand, so no way to know if these will help
Iphone won't easily edit http://forums.adobe.com/thread/881246
-and http://forums.adobe.com/thread/1011411?tstart=0
-and a fix http://forums.adobe.com/thread/934466
In the future, please provide more information, such as this Information FAQ http://forums.adobe.com/message/4200840