Sony Vegas Pro 9 not rendering completely?

I've had Vegas Pro for a while now and I've never had this problem before. Whenever I try to render certain clips, they freeze at 98%. Nothing pops up to stop it or anything, but it stops at that percentage and will not render any farther no matter how long I let it go for. I'm not changing the format or editing anything major, I'm just cropping off the black edges and re-rendering. I'm not sure if there's something wrong with parts of these clips or if that one part is really supposed to be taking hours to render, any ideas would be appreciated.