anyone with a mac???

[numdmind]

Hye...i was wondering how many of ya use macs?  I use divx 2., quicktime, and imovie...hey i'm poor ok. but all of the sudden lately, it will do this thing when i export where it'll only show about the top left corner of my vid and only the first frame.  It still plays as long as my vid was, it just stays on that first frame the whole time.  anyone know how to fix this or have any other suggestions to compress?  thanks in advance.
numdmind