Ardour won't start

I can’t open ardour anymore for a crashed project. I open up a project and then try to open the crashed project but I get the following error:

Session XMLNode describing AudioRegion references an unknown source id = 12198
Session cannot create region
Session XMLNode describing AudioRegion references an unknown source id = 12198

This is REALLY bad since I had recommended Ardour for a pro musicians studio and it is crashing in front of him.

I also had this problem - You have to delete some lines of the .ardour file. Could you upload the file somewhere (not the entire project)?