I just upgraded my domain mapping from version 0.3 to 0.41 which was just released a few weeks ago.
I thought that this might be part of the reason I can't get Multi-DB to work for me.
The problem is that I have members that multiple blogs. They used to be able to jump from one to the other with no problem. This made it real easy to go and write a post for one, and then another, etc...
Now when they move from one DOMAIN MAPPED blog to another DOMAIN MAPPED blog, they are automatically logged out and have to relog back in at a weird URL.. Something like
Again, no problem when they jump from a NON-DOMAIN mapped blog to another.
The old version had a problem with Domain Mapped blogs where quite often you couldn't add links, or insert pictures into the blogs. I think that's been fixed with 0.41, but now this other problem.