dotyet,

Thanks very much for the quick reply.
Yes, I already verified that the services file contains entries that
are in sync with the DBM CFG parameters.
I think the problem may lie with what exactly is considered the
correct cluster.

In Cluster Administrator, the high-level name of the cluster is CLU02.
Under that are two groups, one for windows resources, and  another for
DB2 resources. My sysadmin tells me that these two groups represent
two separate clusters, which can be failed over independently. The
group associated with the Windows cluster has a network name resource
which has a name identical to the highest level in the tre-diagram on
the left of the tool :CLU02

Whereas, the DB2 group has a network name resource which has a name
value of DB201. The only doc I have which describes how to set this
( a redbook)  indicates that when using the db2iclus command to
migrate the instance into the cluster, the cluster name used in that
command is the name of the windows cluster, not the DB2 cluster. I
believe this command also sets the db2 enviroment variable DB2CLUSTER.

If anyone could shed some light on the relationships between all of
these aspects, or some doc that has more detail, I woudl be very
grateful.

Sean