Form-based file transfer

A guy I know using a form to transfer a file to a server (currently on my LAN), but he's having a huge speed problem. Right now, we're using Apache's FileUpload class:
http://jakarta.apache.org/commons/fileupload/

but we're having horrible speed problems in it (I timed each part, and the times I'm about to give are for FileUpload.parseRequest() ONLY.
For a 1.6MB file, here are the times I calculated (3 trials each, averaged):
Internet Explorer: 21030ms
Konqueror: 3100ms
Netscape: 3070ms
Mozilla: 3111ms
Galeon: 3110ms

My question is, why is IE so much slower, and is there some way around this? I used 2 different computers and got similar results. Because most of our target audience will be using Windows with IE, this is a bit of a problem.

Any idea how to get around it?

you can always persuade people into using another browser by putting a link such as...

This is best viewed with _________ and a link to the broswer.

I have been a fan of Mozilla's Firebird/Firefox.