Well, if you're only going to watch them on the computer then they should be fine. The 30MB one sounds suspicious. Are you sure they're complete movies? For people who want to burn them they should be aiming at files that are about CD size.

There's a lot of fakes out there & some are corrupt. Which is another reason to aim at the larger sized files. One of these reasons could explain why you can't play them. If VLC can't play them then there's definitely something wrong somewhere.

Once you've dwnlded them, try opening them directly with VLC (not launching them thru LW.) This will tell you one way or another whether these are reasonable files or not. If yu can't open them then they're corrupt most likely.