Thats a quite old version of JBoss, I can't remember how it was
But I think that run.sh options are not working, this is mentionend in the doc-link you've posted.
I suppose you use the 'all' configuration (I think there was a similar structure below */server).
To disable clustering you should use the 'default' configuration which is without clustering.
An other option will be to serarch the JGroups configuration and find the mcast addresses and change it.
Also, but I'm not 100% sure, is to separate the two instances by different subnetworks, in this case multicast is often suppressed by network.
Unfortunately I don't have such old version and there is no simple download.
But is there an option to switch to 4.x? I know that there is mostly no need if it works
Thank you very much Wolf-Dieter Fink. Was trying to do as much as i can with the jboss portal 2.6 version that i worked with for an application. Unfortunately, i am still unable to avoid clustering. Will post it here if i get any results after some more trial and error process.
Thanks again for the reply.