Classic tween applied, but not rendering

So, I have to take a number of flash files that I created and “stitch” them into one big file. I figured the easiest thing to do would be create one big flash file and then copy the frames from all the separate movies into separate scenes in the big movie, keeping things organized but ultimately in one big file.

So far, I have two scenes. Within the first one everything is fine, and plays normally when I export it to SWF. I should note that for the first scene I just opened up the original file that I’d already created and then started adding scenes to that file, so I didn’t have to copy/paste frames for this first scene of the movie. Within the second scene I copied the frames from another file into the second scene, and while everything looks fine and all the proper files are in the library, the tweens don’t actually work.

They’re there, the frames in the timeline are purple with arrows and everything so it looks like it’s been applied correctly, and in the original file they worked fine. But instead when I play it in Flash and when I export to SWF, the classic tweens don’t work. The images/graphics just appear in different places at the right time instead of moving over there slowly. But Flash says there’s a tween there after all, so WTF? I thought maybe it was a ram issue and my computer (MacBook Pro, OSX) couldn’t handle playing that big a file in Flash (and it’s only going to get bigger, I’ll need five scenes total) but it should work after exporting, and it doesn’t. And besides, everything in the first scene works fine. I thought maybe it was just that tweens and stuff weren’t being applied properly or getting messed up after I copied the frames over so I removed/reapplied them all, but that didn’t make a difference either.

FYI, I’m using Flash CS5 with files set to ActionScript 2 (3 won’t work for the systems I have to place these on later). Any tips?

[SIZE=3]TL;DR[/SIZE]
Tweens are there, don’t actually work. WTF?