I have been working with SWFUpload for awhile now and have had no issues. I've got it integrated into my company's control panel so it will be hard for me to show examples, but ever since upgrading to Firefox 3 I can't seem to get large uploads to work... Here's the details:

I use the File Queue Javascript files without modification provided in the 2.1.0 Demos. It works fine in IE7 and FF2 but FF3 won't work. I can send you the photo if you want to attempt it yourself in FF3.

Now let me clarify what I mean by "won't work." The file uploads, the photo is moved the correct location and the varying sizes are generated correctly and supposedly it prints out "File Received" (I have done manual tests and it does), but Firefox 3 never flips to completed to move on to the next one.

I can get you a working example if you email me directly, but would have to create you an account on an old clients site.

Thanks for the great product and I hope this issue is easy to fix!