I've built a flash uploader to upload files up to 100MB using a php backend. It works wonderfully on our dev server, on a hostgator vps, and on one of our clients' servers running Debian.

It will not work on our Media Temple (dv)3.5 and I don't know why. The upload will start but will choke after a few seconds with this flash error message:

 ioerror: [IOErrorEvent type="ioError" bubbles=false cancelable=false 
 eventPhase=2 text="Error #2038: File I/O Error. URL: 
 http://..._upload.php"]

The problem seems to be specific to the asynchronous nature of the flash uploader because if I try a straight php upload it works fine. The php.ini settings are set to allow such a large upload as well. Also, I've thoroughly googled flash, 2038, I/O error, etc but have yet to find anything that helped.

Here's the weird part though: We work in Seattle. It won't work from the office. It won't work from home. But, while on the phone with MT's support, they were able to upload a file through our flash uploader just fine. I'm not sure where his office was located but I think it was Atlanta. So the problem also seems specific to physical location.

Has anyone run into this sort of problem before?