Getting details of MSCluster_DiskToDiskPartition fails.

Hi There,

 I am trying to collect Disk Partition details from a cluster using the following function .  This is working perfectly fine in most cases.

In some customer places the query '"Associators of {MSCluster_Disk.ID='"& colItem.ID & "'} where AssocClass = MSCluster_DiskToDiskPartition" ' not returning any thing/failing. 

The following is the difference I noticed when the query executes successfully and failed.

1. In Successful case : The value of 'colItem.ID' is some like 4137123909 (i.e MSCluster_Disk.ID)

2. In Failure case : The value of 'colItem.ID' is some thing like '{e13fe43d-7b31-46a3-bad3-b96b6353cbf1}' .  (i.e MSCluster_Disk.ID)

	Function getDisks
		strQry = "select * from MSCluster_Disk"

                Set colItems = wbemServices.ExecQuery( strQry )
		On Error Resume Next

		For each colItem in colItems
			On Error Resume Next

			Set diskPartitions = wbemServices.ExecQuery ("Associators of {MSCluster_Disk.ID='"& colItem.ID & "'} where AssocClass = MSCluster_DiskToDiskPartition" )

			For each diskPartition in diskPartitions

                        'Some Logic here blah blah ....
                        Next
                Next

        End Function

Any help on how to troubleshoot this will be great.

Regards,

Krishna