This is now the second time that it has happened, and I didn't write about it before.
I am setting BizTalk up in a multi server environment where the SQL Server exists on a different machine.
I got the following error after applying the configuration: System.EnterpriseServices.TransactionProxyException
After a couple of hours of going thru database permissions, checking MSTDC settings in component services. I found that on the SQL Server MS DTC was not installed (Add/Remove windows components -> Application Server)