How do I boot .dmg from external HD to Powerbook with brand new HD?

I needed to replace my hard drive on my Powerbook G4 because it was failing according to the Apple genius. I installed it properly by using ifixit.com's instructions. I now need to install an operating system on the laptop but my cd-rom drive doesn't seem to work (it takes the disk, makes some noise and spits it back out). So I need to restore my external hard drive and put a Tiger install .dmg file on it. I can't seem to get any Tiger .dmg install on it yet, it keeps coming up with errors. I tried taking my Tiger install discs and dragging the "Install Disc 1 & 2" into my external hd. Then I plug the external into my powerbook and hold the "option" key. All I get is a rotating arrow box and a arrow box. What am I doing wrong and what do I need to do to get Tiger 10.4 on my Powerbook without using the install discs that I have??? Someone please help

Try cleaning the optical drive with a can of compressed air. Blow a couple of blasts of air in the drive as it may just be dirty. If that doesn't work you'll need to buy an external optical drive and use it instead. Make sure the optical drive is firewire as your PB won't boot from a USB drive.

Powerbook G4's don't boot from USB external hd's??? I'm trying to use my external which is USB to install Tiger on my Powerbook.

That's right, in order to boot your G4 from an external device, it must be FW.