UBB.threads PHP Forum Software Community Forums UBB.classic UBB.classic 5 Support (small) problem with privat forum

Hello,
I`m using the "Ultimate Bulletin Board Version 5.45c" and created several forums, one of them should be privat. After I have logged in with Username, Password an Forumpassword i tried to post a message (as admin). And now the problem: The message does not get postet. There is the errot-message: "You did not complete all required form fields! Please go back and re-enter. "
BUT I HAVE COMPLETED ALL FORM FIELDS!!!

What can I do? Please help me. Thanx
The Url is: http://buyagro.netfirms.com/cgi-bin/Ultimate.cgi

Please open a support ticket for this issue - include ATTN: Charles in the ticket subject and the URL to this thread in the ticket body. Thanks.