I've installed a new beta system which still needs full testing but has worked on every test I've tried so far.
Authors/Uploaders can now choose from two seperate methods of getting their files on the server. The first is the normal upload method good for files up to 50MB in size. The second (new) method is the Transfer function which allows you to select a direct download location for your file and have the server upload the file for you. To futher clarify..
You've uploaded your file to your own webspace or a free upload/download service like RapidShare. You simply need to enter the download location for the file and the system will upload the mod for you straight from the site, saving you a good deal of time being sat around waiting for your upload to finish (and save you some bandwidth!).
This is the only way you can add files greater than 50MB at this time.
As always if anyone finds any issues with the new system please let me know ASAP.