1.- Congrats on getting a PowerBook.
2.- Do you mean that you are moving the entire series of nested folders (Runtime>Libraries>Characters>etc) into Runtime? IF SO, don't. Instead, move the contents of the folders to the appropriate locations, creating new folders as necessary. Use MacInstaller if you want it automated. See Soft-Rabbit.com for deets.
3.- DAZ3D uses .sit files for Mac products, which contain an installer that is ONLY OS 9 (Classic) compatible. To use them you MUST have OS 9 installed. If you are booted in OSX, Classic will start immediately to enable the installers (per default, I believe)
4.- IMPORTANT- Avoid using the " / " (forward slash) character in folder names. The contents will not be recognized. Something about UNIX(?)

Anything else?