General help

I am assuming that the zip files were created using a standard zip package and not some esoteric plugin found in a program or browser. I am also assuming that the files have been downloaded in Firefox and opened properly.

There should be no reason why these files are damaged by IE, but there seems to be so many problems with IE I am probably wrong. I suspect that there is something in your firewall, or within the server, that could be stripping the packets of vital data. A long shot, but that is really the only thing I can think of.