I am also getting the same error.  I have recently been on the clustering course and even the tutors were not able to help with this error.  I have been able to isolate the problem to Dell servers.  This command works fine in a HP environment when and a Compaq environment (when they were Compaq).  If anybody has any idea's on this, I would be truely grateful.  When this working I would not be able to recover without writing the signatures back to the disks.