It probably won't damage the laptop, but it might damage the charger.
The replacement can not supply the same current as the original. This means it may be overloaded.
All is not lost though. The charger is rated to power the laptop *and* charge the battery. If you're only doing one of these, the charger will probably be fine.
I would advise charging the battery in the laptop with the laptop off before powering up the laptop. Alternatively, you could use the laptop without the battery fitted.
Be aware that if your laptop is a Dell, it may refuse to charge the batter if you connect a non-Dell power supply. I'm not sure if other manufactures pull this stupid trick, but beware.
