OK, I may have something. I've looked up the DTSER_FAILURE error and came across this article on Microsoft Support (http://support.microsoft.com/kb/938910). I see that this database server is using SP2 for SQL Server 2005. The referred to article lists some hotfixes to apply and so on, but I'm wondering if it just wouldn't be better to go to SP3 of SQL Server 2005 instead?