Are you sure it's not the error noted at http://arstechnica.com/civis/viewtopic.php?f=22&t=546362 ?
I have always installed Quake 3 Arena on window 7 64 bit
now it would not install it tells me this.
Quake 3 Team Arena Requires A Valid installation Of Quake 3 Arena. Please Install Quake 3 Arena. Set up will now exit.
Any Idea what is going on I bought this game a while ago new, what could have happened.
The computer is still the same setup as what I had it last on the last installation.