Tnx for the Reply. There was a time issue with the ESXi hosts that is why it did not work in evaluation mode.
After fixing the time issue I also did:
rm -r /etc/vmware/license.cfg cp /etc/vmware/.#license.cfg /etc/vmware/license.cfg /etc/init.d/vpxa restart
After this i was able to register the hosts in my evaluation mode vcenter server.