I also tried to install LW in a iBookG4 with OSX 10.4.11 and update 2008-007 but the installer get blocked and need a force quit. I tried the installer in an other machine (MacBook\OSX1 10.5) and the installer crash at the same part of the process: "running the installer script".
I also tryed to download the dmg again and again and always from the official site..

I THINK THAT THE INSTALLER OF THE BASIC VERSION PROVIDED BY THE OFFICIAL SITE SIMPLY NOT WORKS! BUT AS THEY DON'T GIVE OUT A CONTACT THERE IS NO WAY TO INFORM THEM AND WE HAVE TO WAIT THAT THEI REALIZE THE MISS BY THEMSELVES.

(If it's a miss...maybe they just want us to purchase the Pro version but honestly I won't buy a product that I never see working before!)