Superimposed images text expands and contracts after export

Hi all. I'm working on a project where I am superimposing jpeg's of PowerPoint slides over a video track.
In a nutshell, it's a video of a presenter next to a rear projected screen. I took the PowerPoint presentation, saved all slides as jpegs, imported into FCP, put them on video track 2, resized them to neatly fit on the rear projection screen - and since the screen was on a little angle, I had to distort the images a little.
Everything looked good when playing off the timeline, it's when I exported the video as regular Quicktime that I noticed the text from the jpeg slides were constantly expanding and contracting. I tried using different compression settings in the 'sequence settings' to no avail.
Would anybody so kindly tell me what I am doing wrong?


Equipment:
1gig Titanium PowerBook G4
OS 10.3.9
Final Cut Pro v.4.5