Re-enable Hibernate Properly and Perfectly in natty

I installed a fresh copy of Ubuntu Natty. I used it quite well for some time. I disabled swap partition and the result is that my hibernate option in the menu was gone. Then i created the swap partition and enabled the swap and restarted. Now i can see Hibernate option in the menu.

But now, after hibernating and waking up the application and windows that were open are now closed. It is like just shutting down. My swap partition size is of 3GB. I am using nvidia graphic card.

Later i installed hibernate script by command line
$sudo apt-get install hibernate
and used it to hibernate.
$sudo hibernate
Then the output is as follows :
hibernate:Warning: Tuxonice binary signature file not found.
Some modules failed to unload: nvidia
hibernate: Aborting suspend due to errors in ModulesUnloadBlacklist (use --force to override).

Please help me to re enable the Hibernate option which worked quite well previously.
Thanks to all in advance.