Hi Ashok, community releases are community supported and AS 5.1.0 is nearly ancient history which makes it less worhtwhile.
However I did manage to use Infinispan 5.x in AS 5.1 at some pointbut only when NOT using the AS clustering, i.e. the "all" profile (because the version of JGroups is incompatible).
You need to play around with classloading to get this to work (sorry I don't have access to that deployment anymore).
I really strongly recommend upgrading to AS7.x.