I'd look around in Power Management Setting. If all looks correct, change it to another configuraton such as how many minutes before screen goes black etc, and then reboot, then change it to the configuration you want and reboot and see if that works. This will force writing of the correct power management settings to the registry. There should be an option under power management to have it hibernate when lid is closed, which should already be selected.
Other than that you could always backup your data to an external drive and then rebuild your laptop from the system restore DVD's or chose a earlier restore point and see if the system behaves when lid is closed after reverting to an earlier point in time of system state.
*The only time I have seen a hibernation crash was when a hard drive is just about completely full and so Windows is unable to write from RAM the system state to hard drive, and so it crashes due to not enough free space to send the image to. How much free space do you have on your hard drive?