Are you sure the WAN IPs should be set to 192.168.1.100? Could you try to leave them blank or to put them as your public IP?
Also, and just in case, could you take a look at the Firewall tab in the "Security and Privacy" System Preferences on OS X?
It should be off:
Have you checked that with the same settings and another computer you can access port 8080? If not, it is most probably related to your routing settings.
Hope it helps.