Sql Server Reporting Services - Errors and Solutions

Error - 1

The report server cannot decrypt the symmetric key used to access sensitive or encrypted data in a report server database. You must either restore a backup key or delete all encrypted content. Check the documentation for more information. (rsReportServerDisabled)

Solution:
Check the microsoft KB article at the following link.
http://support.microsoft.com/kb/842421

Error -2
The permissions granted to user are insufficient for performing this operation. (rsAccessDenied)

Solution:
Apply the permissions to the user as mentioned in the below article.
http://msdn2.microsoft.com/en-us/library/aa337471.aspx
If you are using Team Foundation Server, check the following link.
http://team-foundation-server.blogspot.com/2007/09/permissions-granted-to-user-userid-are.html