Q: After I convert Final Cut Pro 7 edited footage into Quick Time, parts of it come out jerky.  Please help.

I am a technoidiot but have managed to produce several music videos on my husband's Mac using Final Cut Pro 7.  However, when I converted this last one into QuickTime parts of it came out jerky, and this happened each time I converted a test video, to a lesser or greater extent.  I edit in Mac OS X, 10.5.8 on OS 1058, whatever that means.

This is the first time the jerkiness has appeared since I've started editing music videos, and I can't figure out what I've done differently to cause this.  In all cases I use jpegs for the still images, and I pan and zoom.  It's during those pans and zooms where the jerkiness occurs.  It appears at random places during different test versions of the same video.  Can anyone please help me, using plain English and not so much technical talk?  Thank you!