[otrs] Customer: Creating new ticket problem.

I'm logged as a customer at http://helpdesk.openware.biz/otrs/customer.pl I go to new ticket, I fill in the "Subjetc" and "Text" fields. The field "To" has only one option: "OTRS System - Queue: Postmaster - master queue". And click on "store" boton. At the browser title appear "HTTP 500 Internal server error" And shows the page titled: "The page cannot be displayed" The same occurs when I tried to store a phonecall logged as an agent. What can i do?