I think I know why files are corrupted:

I notice that the Mac version only handles the first 40 (or so) characters of a filename. If the filename is longer than that, LimeWire thinks the files are the same, even though the name differs at at the end. Of course, we assume that the length of these files is the same.

You can observe this beaviour when you see two files with differend names grouped together. I have reported this problem with v2.4.5 but the developers never respond and maybe also not read email messsages.