Ok, I just downloaded BG2 and had...something of a botched modding attempt with the BiG World installer, so I decided to uninstall and reinstall the game. But when I tried reinstalling, I got a message that there was some kind of error with the links in the game's "mplayer" folder. I think the installer tried to overwrite them and couldn't for some reason. I tried deleting them, but keep getting a message that they won't delete. Apparently they're either write-protected or in use, but I can't figure out how to disable write protection if that's the problem, or how they could be in use when I haven't opened them or anything. Does anyone have a solution?

That did it. I restarted the computer and the offending files were gone. Thanks!