Cannot debug stored procedures because the SQL Server database is not setup correctly or user does not have permission to execute master.sp_sdidebug.
SQL Server 2005
When debugging stored procedures, the debug process fails if a SQL Server login user does not have Execute permission granted to the extended stored procedure sp_sdidebug in the master database.
To debug stored procedures, you need to have appropriate user permissions to execute the extended stored procedure sp_sdidebug. The default access is for system administrators only.
This error can also occur if the SQL Server database debugging software (both server-side and client-side) is not setup correctly.
Other Resources
How to: Enable SQL Server 2005 DebuggingHow to: Set SQL Server Permissions for Debugging
