Unable to mount/unmount or drop ASM diskgroup in RAC

Hi,

I have a 2-node RAC database on Oracle 10.2.0.4 on AIX 5.3 using ASM. Sometime ago there was an issue while adding new disks to an existing diskgroup which resulted in the disks not reflecting the correct status because they were used in a diskgroup of the same name on a different database.  We had to run the dd command on the disks to clear the disks headers and we were then able add the disks.  Subsequently all the disks were dropped from the diskgroup and the diskgroup was dismounted.  Now the diskgroup cannot be dropped on mounted/unmounted.  I tried