Thanks for the links, but none of them look any similar to my issue.
Found the resaon behind these. They were beacuse of conflicting database jar. I had my H2 database seperately and the client jar which was present in jboss was not the same version as that of the server.
Thanks all for help extended.
Could you please give some details how you could solve this problem?
I don't know how to fix this database missmatch you mentioned.
Thanks a lot.
The database library file is kept in jBPM5.2\db\driver folder. The version of this file was different from the version of H2 database that I was running.
So, in order to reflect the proper db driver, I changed the file in jBPM5.2\db\driver, ran install.demo again and then started the server.
Hope this helps.