also, what resolution are we talking about? how are you previewing your file?
try this: drag your footage to Ae and load it to cache (numpad 0 set it to cache before preview) and preview it. does it preview fine?
If I cache the .mov file in AE, it does play, but only 200 frames or so at a time. Is there no way to play it in Quicktime?
I wanted to make sure there isn't a problem with you video, just with the playback. Photo-Jpeg isn't the best codec for playback, it's considered a virtually lossless codec and usually not for playback purposes. if you wan't a decent playback, you should render your video Through Adobe Media Encoder with H.264 preset. see it here: Basics of rendering and exporting in After Effects CC
Thanks for your help, Roei. It seems it will play in pieces in AE. I'm still not sure how to view the whole thing. I'll check out the link you sent.
AE's preview caches to your RAM. If you want to preview your whole thing, you will need to either add more RAM or reduce the requirements. Most AE professionals don't preview their whole comp at full resolution, by the way. Spot check things here and there, sure, but not the whole thing at full size.
Change your comp down to half resolution and it should be able to cache a lot more of it.
Were you ever able to export your video? Please let us know if you did or if you still need help.