R unable to run on Mac OS 10.4 Tiger

I suppose i will have to reinstall quicktime 7 and things will be  
OK. But I don't understand why R does need quicktime ??

Neither R nor R.app does. Chances are that you pretty much broke your  
Tiger, because all R.app does is to link Cocoa which links AppKit. On  
my Tiger machine it doesn't even touch QuickTime, so it must be your  
plugin or whatever you did to poor Tiger ;). Why don't you just  
remove /Library/Quicktime? It's not a part of Tiger. Tiger's  
QuickTime files are in /System/Library.

If you want to understand better who's loading what, set  
DYLD_PRINT_LIBRARIES when running R or R.app.

Cheers,
Simon