Hi Marc,
this question is a bit flavoured like this:
"My car is broken down! What can i do?"
- Maybe you have no gateway configured.
- Maybe the wrong interface configured
- Maybe ....
What interface 0 have you configured? FastEthernet, Dot11 ????
Please give us some more details. Post your configuration (show run).
Do you use VLANs?
Best Regards,
Frank