This operation can be performed only on a computer that is joined to a server farm by users who have permissions in SQL Server to read from the configuration database. To connect this server to the server farm, use the SharePoint Products and Technologies Configuration Wizard, located on the Start menu in Administrative Tools.
As the error suggests, did you check your SQL db rights? Do you have enough rights on the config db?
Visit a similar post in msdn having the same issue - http://social.technet.microsoft.com/Forums/en-US/sharepointadmin/thread/666ba20b-eba5-4c2b-a7d3-bfb03ca56b91/