You got to open the command promt on WinXP and type ( with quotes )
If that doesn’t work you can drag the xampp_start.exe from your installation folder onto the command promt and press ENTER. ( this works for other stuff to, try it )
This will give you more information on why things fail, it helped me hunt down a bug which I could trace back to my configuration of httpd-vhosts.conf and httpd.conf. A network drive of mine refused connection and triggered errors when starting Apache from my Xampp control panel.
Which makes me think: Why o why do women don’t have a cmd prompt 🙂