The problem here is that at that point a script is running to create the initial configuration of the database.
This is showing me that there is a problem with windows scripting on the affected computers. It makes sense since the affected machines are 2003 and xp based.
I would not replace the machines or OS - maybe too much hassle. However you cannot blame the installer because it depends on the windows script engine on Windows OS.
I would try and upgrade windows installer version on your computer to the latest version.
I would try and give full windows updates
I would update windows script version example in this microsoft guide
http://support.microsoft.com/kb/949140If all this fail go to %temp% and locate the installation log file of 3CX. There will not be much information about the error but could help us find a solution.
Definitely something is wrong on the OS however so make sure your troubleshooting efforts go in that area.
Thanks