I replicated it using a 74 mb file. Let me know what the file size of what you're uploading so I can get a better idea of the range it goes bonkers on. We'll troubleshoot this further and see how to fix it. All things on server settings seem ok but there has to be something we're missing.
Ok, looks like the problem is fixed. I test uploaded a 74 mb file and it worked. On a standard 1.5mb upload connection, you should be able to upload 100 mb files without a problem