I haven't had that problem, and I've submitted a batch most every day.  Have you tried using a different web browser for your submissions?  That may get you past an error which may be related to browser incompatibility, and at the very least will eliminate one set of variables (including errors in cookies stored on your computer).

As a separate issue, I'm guessing you don't edit keywords and descriptions in your files before you upload them.  That's a very bad idea.  Get some software that will let you insert them directly into the file, so each agency will retrieve them automatically.  That will at least speed up and simplify the process of resubmission if it proves necessary.

Also, have to tried the Save button before you hit Submit?  If that works, it will save all your keywords, description, categories and release information.  Makes retrying the submit much faster.

I was also having the same problem. Disorderly is right changing browsers solved the problem.