can you access the boxes via any other methods? Do you have ssh, ftp, nfs, or any other services enabled? If you cannot access via these protocols, then there may very well be something wrong with your firewall configuration.
On a related note, it is a different setting to permit pings to the firewall than it is to permit pings on the local network protected by it. If I may recommend a different setup, especially for home use:
try not to have your firewall managing internal routing, especially if you have decent practices on the computers within your local intranet.