First of all, you submit your script via the e-mail given to you from the submit page you are trying to open. You don't submit it directly from that page. But, the scripts database is down at the moment because of a problem. It will be back when the problem is fixed. I don't know the address you need to send your script to, but even if you send it now, it will not be added till the problem is fixed.
P.S. I guess the address is scripts@msgpluslive.net but I am not sure.