Movie editing. [Question]

[Fathom]

Does any one on this forum use Final Cut Pro v.3
I'm having problems with the speed on certain clips.  I set the speed to anything above 100% for an individual clip and the program tells me that the command can't be executed due to a trim problem.  It's weired because 4 days ago I was able to do what it isn't allowing me to do now.  The only thing I've done since those 4 days (If I recall correctly) is adjust a few key frames.  WTF is wrong?