Two things, that iBook will never run Jag efficiently. Mainly that old ATI iT or whatever is way to slow for the graphics, and the VRAM can't be uped past 16MB, this prevents you from using any of Quark Extreems capabilities. The second thing is, well, you need more than 64MB of ram... minimum 128MB of RAM to even install Jaguare.
Sad but true, OSX is a resource hog. I admit it. For older machines like that, I deffiently recomend good ol' classic.
Ironicaly on my TiBook 400Mhz I run Jag flawlessly. It has 387MB RAM, an old ATI card too. But since OSX is G4 optamized the performance is amazing.