I think the newer AMD drivers are "fail" with this version of guiminer. Would you agree? Thoughts?
I can't help much except to say that I installed the new 13.4 Catalyst driver yesterday on a 7970 and have been mining with it using Guiminer on Slush's pool with no unusual behaviors.
I'm using the standard "slush's pool" connection, not a custom port with "other". I did that recently also with no problems, but I can't remember if it was before or after the driver update.
I'd guess it's not your new driver, but who knows.