Recently one of the support staff at my company, Daniel Tran, found that one of our clients running a BizTalk 2009 BizTalk server was not processing messages, and errors in the Event log indicated an issue with the SSO database. To resolve this he had to contact Microsoft, and he was advised to follow the steps in the following blog: Continuous Arithmetic Overflow exception with SSO in BizTalk Server.
Essentially a table in the SSO database had reached the maximum int for the primary key in that table. And the solution was to start it back at 1 again. If you are running any older BizTalk environment, it might be an idea to check the SSOX_AuditXPLookup table to ensure that it isn’t coming close to this as well.