There are six potential causes for this error:
Cause 1
If the Management Reporter Process Service is on the same machine as the machine hosting your ManagementReporter SQL database. The Process Service may have errored out by attempting to start before SQL Server was accepting connections. See Resolution 1 in the Resolution section.
Cause 2
A SQL Server connection error has occurred and the Management Reporter Process Service needs to be restarted. See Resolution 2 in the Resolution section.
Cause 3
The user running the Management Reporter Process Service does not have sufficient permissions to read from the ManagementReporter SQL Server database. See Resolution 3 in the Resolution section.
Cause 4
The SQL Service Broker on the ManagementReporter SQL Server database is not enabled. See Resolution 4 in the Resolution section.
Cause 5
This can happen if the owner of the Management Reporter database is a Windows User while the SQL Server Service is being run by a local user. If you check the Event Viewer, you may see this message:
An exception occurred while enqueueing a message in the target queue. Error 15404, State 19. Could not obtain information about Windows NT group/user 'domain\user', error code 0x5.
See Resolution 5 in the Resolution section.
Cause 6
This can happen if the "no count" checkbox is selected in the Server Properties in SQL Server Management Studio. If you check Event Viewer after generating a report, you may see this message:
System.Data.Linq.ChangeConflictException: (Row not found or changed) or (in Assembly 'xxxxxx' is not marked as serializable)
See Resolution 6 in the Resolution section.