Hello, I have recently upgraded my zen cart from 1.3.9 versions to the 1.5.1 and now I can not log into the admin tool area and continue to receive 404-error message "The requested URL /padmin/FILENAME_ADMIN.php was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request."

Please help, I was able to locate the file and see that it exist in on my server but for some reason I receive error message...