weblogic cluster 6.1 urgent

I am having difficulty in starting the clusters .
Here is my setup .
Unix Server1 has three weblogic instances named
peoplesoft , clustA, clustB .
peoplesoft instance will be the adminstrator and clustA and clustB weblogic instances will be clustered .
I logged into http://server1:8020/console .
Under my servers list , i find 4 servers which are
ClustA
ClustB
PIA
WeblogicAdmin
under my clusters folder , i created a cluster instance named MyCluster which has the below entries
ClustA
ClustB
My cluster propertes shows
cluster address as server1:8040,server1:8050
default algo as round-robin
and given default values under the multicast .
also under the servers tab in the clusters directory
available servers --> PIA , weblogicadmin
Choosen ---> clustA,ClustB
under the monitor tab
Number of Servers configured for this cluster: 2
Number of Servers currently participating in this cluster: 0
now i started up by admin server using startPIA.sh .
when i start my managed servers using startPIA.sh my web servers are starting but there are not participating in the clusters
. If i use the startManagedWeblogic.sh PIA http://server1:8040 ..
i am unable to startup the managed server ...
Please tell me what is wrong ...
***************************************************************************
The WebLogic Server did not start up properly.
Exception raised:
weblogic.management.configuration.ConfigurationException: The name of the managed server is same as admin server. The managed server
will not be allowed to start up.
at weblogic.management.Admin.getBootstrapLocalServer(Admin.java:1149)
at weblogic.management.Admin.initialize(Admin.java:344)
at weblogic.t3.srvr.T3Srvr.initialize(T3Srvr.java:365)
at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:212)
at weblogic.Server.main(Server.java:35)
Reason: Fatal initialization exception
***************************************************************************
Please tell what is the problem

shut down all instances of weblogic, start the admin server using startPIA.sh, open up the console u should see the admin server running and the other 2 managed servers listed but not running,
next start the managed server using
startmanaged server admin url managerservername1
startmanaged server admin url managerservername2
let me know if u still have problems.. dont define too many systems, keep a clean config.xml, open ur config.xml and check the settings if req.

I forgot to tell u something. in weblogic 6.1 u cant make a cluster of servers running on the same ip. the weblogic instances need to be on different ips.. 7.1 onwards u can run more than one server instance on the same sys..