SQL Server service where your stored procedures are located must be running
under a Windows NT user account that has administration privileges to the
server. Debugger can't run if SQL Server is running under a local system
account. To check the type of account your server uses, go to Control Panel [/ref]
and you will see Service dialog window. In the Log On As tab, uncheck the
System Account option button and enter the account username and password in
the fields located in the tab. The username can't be LocalSystem, the
account user-name and password must be for a user.
Refer to following topic in BOL
"Troubleshooting the Transact-SQL Debugger"
"Daniel Walzenbach" <de> wrote in