Hi Rakesh,
I am out of office right now, and can look into your issue more deeply only in a week, but until that, if you have build start problem, take a look at this, you'll find it really useful:
(NWDI)(CBS)Q0010 - Technology Troubleshooting Guide - SCN Wiki
Indeed your setup looks ok. Most likely we don't need to spend more time on the JDK related settings, if your current problem is that the CBS is not picking the build requests for processing then look into the above referred TSG link.
Cheers,
Ervin