Error code 0x5. [SQLSTATE 42000] (Error 15404): Could not obtain information about Windows NT group/user

Error 0x5 means access denied.

Try to changing the owner of the jobs to the ‘sa’ account, on the properties of the job.

If the above does no help, please change the service account for the SQL Server agent service to account with proper permissions.
http://technet.microsoft.com/en-us/library/ms345578.aspx

I hope this will helps .