List of Biztalk Errors and warnings: causes and solutions
On the techNet wiki there is a new post on BizTalk errors and warnings.
The article is yet to be expanded.
The point is to get a complete list of possible BizTalk errors and warinings with their causes and solutions for all stages/components.
For now the list is still rather limited, but with the contribution of all of you this list can become complete.
List on TechNet Wiki: BizTalk: List of Errors and Warnings, Causes and Solutions