Required Permissions in SharePoint Farm for executing PowerShell scripts
Before you execute any of the SharePoint Cmdlet you must be sure that you have necessary permissions to execute in the farm. Also you must have access to local WSS_ADMIN_WPG group where you are executing the cmdlet. Also you must be member of the SharePoint_Shell_Access SQL role within the databases your cmdlet calls in to interact with. Some commands also require you to be a member of the local administrator and farm administrator grooups. For ex. to create a web application, you must be a local administrator and farm administrator. In Regards to adding users to the WSS_ADMIN_WPG group and SharePoint_Shell_Access SQL role, you must not be adding users directly to these groups rather you should use Add_SpShellAdmin cmdlet. This cmdlets accepts optional database name as parameter. If you do not pass this parameter it will add the user to the SharePoint_Shell_Access SQL role in the SharePoint configuration database only. Above third line of c...