Well, I can't speak for your installation - but I (personally) have installed in now on over a dozen machines (and USB Sticks) and it has always worked.
I looked at your old post, and I have the same comment that was true then - something is blocking Port 80.
Is this a peer to peer Windows Network?
A firewall that allows WAMP - would usually be tuned to the installation location (path) of THAT copy of httpd.exe, but not the copy installed with XAMPP (which persumably would be in a different location) - so the logic you propose is not true.
you should check whatever firewall software it is, and make sure there are exceptions on Port 80, the right subnets, and the XAMMP copy of httpd.exe.