Q: My current os x is 10.9.5, using final cut express vers. 4.0.1.  I have imported .mov clips created with a older mac os x (lion) and converted them to import into fce. after doing this as well as putting clips on the fce timeline when playing back t.h

My current os x is 10.9.5, using final cut express vers. 4.0.1.  I have imported .mov clips created on a older mac os x (lion) and when I wanted to import them into fce, a quicktime conversion window opened up and converted them (I haven't experienced this in the past). I then imported the converted quicktime clips into my fce project.  After doing this I took selected clips and put those edited clips on the fce timeline.  When playing the video back in the fce timeline,I noticed

1) the video wasn't playing back smoothly like the original content

2) when looking at the timecode reading of the timeline, the timecode was sputtering as well as the video and audio.  I exported to quicktime just to see if that was consistent, it was.

When I play the converted quicktime content independently of fce,  it plays normally (no sputtering of timecode, video and audio.  Need help to resolve the sputtering playback of converted video content in the fce timeline.  I've never experienced this before.  Any suggestions?