Can you please zip your music database and attach the zip file here
(if you are not sure where music database file is located look at Folder/File Locations - MediaPortal Wiki)
ok database seems fine but the exception is something to do with a path. Unfortunately I am away with work and I don't have the MP 1.1 source to build a version of this for debugging.
The error you are getting is about an invalid path. This could be a couple of places. Can you try turning off audio scrobbler plugin?
Also does this happen 100% of the time? Does it happen in both shares view and database view?
You have not done anything odd with the thumb folder?