Can XAMPP bypass 10.5 Server functions to host to Internet?

[proparanoid]

I purchased a G5 with 10.5 Server to host 3 low traffic Web sites, and to access specific apps of interest already installed —but the server side will not function. Reinstall of OS does not proceed according to Hoyle when transitioning to the second disc; it refuses to recognize any server set up in the first disc routines. Troubleshooting suggests the second disc serial number does not match the first disc, as there are select points in dialog routines where it indicates the serial number is invalid, though direct from the package, and it is accepted on install. I can't downgrade back to 10.5 non server and use Web sharing without loosing my applications. Someone suggested XAMPP which I have installed, but nowhere do I see any way to use it to actually HOST (not virtual host) Web sites. Any Web references to using XAMPP for hosting are far too vague (like ten words) and address 10.5 or 10.6 non server, wanting me to turn on Web Sharing, which does not seem to exist on Server versions, though I've seen references to ways to 'turn it on' which require the Server Admin which is inoperable due the serial number issue. It does not make sense to me to spend as much as I paid for the G5 to buy a new install disc set if XAMPP can solve the problem.