I'm getting the same problem. I downloaded Limewire Pro and tried to install it on my WinMe eTower 400idx 256meg 40gig HD; I was able to install 4.2.6 and it was running with no problems. Updated to latest isScript 7 and Java 1.4; I get the following error messages:

To run a silen install you must either specify a reponse file or override this event (OnMsiSilentInstall()) and provide your own implementation.
The setup will now end.

Error: -1603 Fatal error during installation.
consult Windows Installer Help (Msi.chm) or MSDN for more information.

I've been through several suggestions but continue to get this error message. Any thoughts or suggestions are welcomed...

Thanks & happy holidays...