Cubase LE doesn't launch

I’m a Cubase 6.5 user that still has an old iBook PPC G3 with Cubase LE installed on it - but the iBook wasn’t used for several years now. I wanted to re-activate my iBook for travel purposes and re-installed OSX Tiger 10.4 from scratch and went through all necessary steps to make Cubase LE active again (installing the latest version of LE4, installing eLicenser, asking for a re-activation code a.s.o.) Basically everything is set up to run Cubase LE 4 again, but the application simply doesn’t launch. After clicking on the Cubase icon in the app bar, it jumps up and down for about 5 seconds and that was it…

I’ld really appreciate to have my iBook running nothing else than Cubase LE4, but I can’t find any solution to make it work. Who has any hints on how to make this work again?

Thanks a lot for your insight,