When the first configuration import in a complete import process fails, users may get 404 HTML error

A configuration import error during the first part of a complete import may produce a 404 (page not found) HTML error.

Users would typically find that they ran a simulation import, it went fine, and few seconds after hitting "Next" they would see the page with the 404 error. This masked the real configuration import error and, as a result, made support quite difficult.

The fix restores the normal error reporting functionality in these cases.