That isn't one of the errors commonly associated with cache. You could try clearing the server scripts from the menu option Site->Advanced->Remove Connection scripts.
I haven't seen the issue you are reporting, so I can only guess. If the other connection works, then it wouldn't seem to be an issue with your site settings, but usually connection problems are issues with the URL in the site settings.
What about screen sharing? Could we set up a screen sharing session so I could debug it from your computer without getting direct access?