You used the wrong forum, the Clustering Forum might be more appropriate
http://forum.sun.com/jive/forum.jspa?forumID=295
I have cluster 3.1u2 version. Will thi support SOl10?
Or What version of cluster is supported in Solaris 10 ?
What did you do to investigate the issue besides posting this inquiry (e.g. searched SunSolve, read the Sun Cluster Release Notes/Installation Guide) ?
These are just hints.
MIchael