UPDATE 7/18: We have fixed the issue. I blame Leo for breaking it. Go back to your normal uploading.
Just an FYI: We're aware there's a problem with uploading files to SpeedZone, which appears to have arisen from the recent update of our site to vBulletin 4.1.4 and the new post editor. The ETA to fix at the moment is 24-48 hours, but may be extended due to other issues.
We're sorry for the inconvenience. In the meantime, we encourage all cursing to be directed to vBulletin Solutions, Inc., as that is who I am cursing out at the moment.