Permissions for Report Builder in GP 2010
1. Go to SSRS Report site ex: http://reportservername/reports¬_instance
2. Go to Site Settings in the upper right
3. Choose Security on the left nav bar
4. Add the user or group as DomainNameUserorGroupname
5. Select the “User Role”
6. Go to SQL Server Management Studio
7. Add user or group as SQL Login
8. Map new security login to the appropriate GP databases and assign DYNGROUP role.