AvailableDisk.AddToCluster() throwing System.Management.ManagementException with message generic failure

I am trying to add available disk to cluster using c# wmi calls. I have generated the class with visual studio.Disk is added to cluster successfully . But in the end it is throwing exception.

System.Management.ManagementException was unhandled by user code
  HResult=-2146233087
  Message=Generic failure  
  Source=System.Management
  StackTrace:
       at System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode)
       at System.Management.ManagementObject.InvokeMethod(String methodName, ManagementBaseObject inParameters, InvokeMethodOptions options)
       at CloudStack.Plugin.WmiWrappers.ROOT.MSCLUSTER.AvailableDisk.AddToCluster(String ResourceName, String& Path) ROOT.MSCluster.MSCluster_AvailableDisk.cs:line 919