Last beta of TOAD SS 184.108.40.2069.
I connect to a server.
On main toolbar I select button - compare and sync schema object - .
I press cancel when schema compare wizard appear.
On toolbar of Schema compare Schema comparison window I select button - Get Schema compare snapshot(s) for project database.I press next button on Schema snapshot wizard and press cancel on window - select database for get snapshots.
At this point appear exception that you can see in attach as screenshot.