Been playing on EZ for a few months now, finally posting on the forums because I had a similar problem to Bladethorn and it was not obvious what was going on.

What it turned out to be for me was some kind of decompression issue.  I had extracted UF using the win7 build in decompression, but on to a compressed volume.  I finally used 7zip to decompress it, and on to an uncompressed volume, and the problem went away.  I dunno which of those things made the difference.