I have installed the free version of sql server 2008 (sql server management studio express edition) on my PC. After installation I get the following error
You should use sp_addsrvrolemember to add your user into role 'sysadmin'. Here is link that helped me to solve this problem: http://social.msdn.microsoft.com/Forums/en-US/sqlexpress/thread/76fc84f9-437c-4e71-ba3d-3c9ae794a7c4/