source file is different from when the module was built.

This commonly means that the code you are debugging in the db layer has had build errors, and you are running with an out of date version. If this is the case, fix and rebuild the db layer.

An alternative reason for this happening is that the PDB files have not been refreshed when building. Do a "build clean", and then rebuild the solution (actually go into the output directories and check that the files have been removed before you rebuild the app).