When I attempt to upload a new mod to WH2's steam workshop through the TW launcher, it starts and immediately terminates the upload/update progress bar, and I get the 'Failed to create mod in Workshop! k_EResultFail' error message. Thumbnail filename matches that of the mod, it's the right file size and format, and fits the required 256x256 pixel dimensions. All attempts at troubleshooting so far have been futile. Please help.

I will bump this until someone at CA sees this and gives me closure. I deserve at the very least to know what's wrong! And no, it's NOT a packfile problem, and my thumbnail is, in fact, NOT the wrong size/dimensions/name. The problem is completely unidentifiable and unfixable.