When using the uncomment line hot keys (ctrl+shift+minus) with the cursor at the beginning of the line, before the first dash, an error is given. If you do this anywhere else on the line it is OK.
"Length cannot be less than zero".
WORKAROUND:
Place the cursor somewhere else on the line and use the uncomment line hot keys.
STATUS:
Issue fixed in version 3.0. The latest version of Toad for SQL Server can be downloaded here.