"Bad Request" when trying to add file to Source Co

Hi, I'm currently using the RTC Sandbox via the Web Interface, trying to add a file to Source Control.

Whenever I click the 'Add File' button on the top right of the screen, I get a popup window saying "Bad Request", presumably this is when the select file dialogue is supposed to appear?

I should add - I've tried this on IE8 and FF5.0, both with the same results.

Any help much appreciated!

Thanks, Jamie.