IE Access limited

We just finished installing a new Dell Server with SBS 2003 and we are using a Firebox SOHO 6 router for the firewall.

After getting everything set-up and running I went back and was double checking the work stations and found that four of them no longer have Internet access.

Three are XP Pro and one is a Win 98SE Laptop.

I double checked all of the settings, released and renewed the IPCONFIG on them. I can ping the firewall but can not access or ping anything beyond it with these four machines.

The other four machines are working just fine.

Thanks for any assistance I can get.