You receive an "Invalid Class String" error when SQL Server connects to a Cluster Server through the Cluster Administrator

The following error message may display when SQL Server connects to a Cluster Server through the Cluster Administrator. For instance, if the Microsoft Search Service is not available, the following error message may occur: The resource type that appears in the error message may be different depending on your specific environment.

The error message occurs because of one of the following reasons (the DLL or resource may vary depending on your environment):

• The Microsoft Search Service resource DLL file, Gathercl.dll, is not present in the %systemroot%\Winnt\Cluster folder.
• The account that is logged in does not have sufficient permissions to access the folder.

To work around this problem:

• For the example error message listed in the first bullet item of the Cause section, make sure that Gathercl.dll is present in the %systemroot%\Winnt\Cluster folder. If Gathercl.dll is not present, copy Gathercl.dll from the SQL Server CD and place it in the %systemroot%\Winnt\Cluster folder. Register the DLL by using Regsvr32. If you have a Service Pack installed, copy the Gathercl.dll file from the Service Pack files.
• Make sure that the account that you use to login to the Cluster has full control over the %systemroot%\winnt\Cluster folder and all the files in the folder.