[otrs] error creating ticket from POP3 account

Hello everybody, Since a few days I am not able to create a ticket from email picked up by the POP3 account. When I execute POP3Master.pl it says that it cannot handle a ticket priority of NULL and cannot create the entry in the database. I think the solution will be to set a default priority of 3 for tickets that are created from mail. But I cannot seem to find where to configure this. I am using OTRS::ITSM 2.2.2 on Apache and Server 2003. Thanks, Peter