Unable to get SSMS 2008 r2 express remote debugging to run properly using Windows 8

I am unable to get SSMS 2008 r2 express remote debugging to run properly using Windows 8.
Sometimes (maybe 1 out of 20 times) it actually works, it takes a very long time before it stops at the first line, but then I can step into the code.
But usually I get an error running  remote debugging:
‘Unable to start T-SQL debugging. Could not attach to SQL Server process on <machine name>. De service voor verificatie is onbekend.’
The last part is in Dutch and translates to something like: The service for verification is unknown or Unknown verification service. 
If it does not starts properly or throws an error I get something like this:
< ...