You can't restore a Time Machine backup made with Snow Leopard onto a system with Tiger. You can, but you will damage Mac OS X.
In order to restore your Time Machine backup, you should have your Snow Leopard disc. Then, insert it and hold the C key while your MacBook Pro is starting. Finally, choose your language, go to Utilities menu (on the menu bar), choose the option to restore the backup and follow its steps, so you will recover Mac OS X Snow Leopard