The way I got it to work when having a similar problem was using PHP 4
The way I did this was to -
1. remove all traces off the first XAMPP install using system restore point. If you have to do this manually then I would use all the uninstall options you can and check the services running on the PC to insure that MYSQL is not present.
Once you are back to a clean state (no mean feat if like me you tried installing bit manually (i.e. mysql)
***While I managed this on my laptop, my other XP PC - I just can not get to work it complains about:
"[Sun Aug 08 11:00:41 2004] [notice] Disabled use of AcceptEx() WinSock2 API (OS 10048)Only one usage of each socket address (protocol/network address/port) is normally permitted. : make_sock: could not bind to address 0.0.0.0:443 no listening sockets available, shutting down Unable to open logs"
Unfortunately, I can not use system restore on this PC as I have made to many other changes that I need to keep. I tried removing all the apache /mysql reference from the registry etc but I think I have screwed it up even more.
Assuming that you have managed to remove all previous installs -
2. re-install xampp in to for example C:\xampp - run the install batch files and see that its working -
3. then use php-switch.bat to change to PHP 4.
4. Copy Mambo install in the a directory off the HTDOCs - then before runing the application - e.g. c:\xampp\htdocs\mambo
5. create a database for mambo e.g, mambo (keep a reference of the user name and password)
*don't remove any of the directories yet
6. Run up xampp if its not running already and go to the install page for mambo e.g. http://localhost/mambo
- then install away...
interestingly once installed and working - I tried going back to PHP 5 (it just crashes out..)
-- this is not an ideal solution but hopefully it will get you up and running