WORKAROUND #1:
Ensure the account running the discovery has local admin and sysadmin access on the SQL server that is producing the error. To verify that the node server can enumerate the instances on the remote SQL server, follow the below steps:
1. Log into the server that hosts the ER node using the service account that is used to run the SQL discovery
2. Go to Start then Run and type in 'wbemtest' and hit enter
3. Click on the Connect button and then for the namespace type in:
\\SQLservername\root\microsoft\sqlserver
4. Click connect
5. Click Enum Classes...
6. Click Recursive and then click OK
7. Scroll down to "__NAMESPACE" and double click it
8. Click on the instances button on the right hand side
9. Provide a screenshot of the namespace list
WORKAROUND #2:
If access has been verified and the issue still persists, contact Support (1-800-306-9329) and request a hotfix for defect ID TF00428781