Q: My O, L, and '.' keys are not working!

Try,

Unplugging the PowerBook. Remove battery and then hold the power button for five seconds.

Put the battery and power back in and try your keyboard again.

Best of luck

Sounds like a cracked trace on the keyboard PWB.  Best to just replace the keyboard.  You might get more information at this link:

http://www.powerbookmedic.com/Powerbook-Keyboard---G4-Aluminum-p-16506.html

Replacement can be a bit involved:

http://www.ifixit.com/Guide/Installing-PowerBook-G4-Aluminum-15-Inch-1-1-5-GHz-K eyboard/223/1

In this case, the Titanium models have the Aluminum models beat, as replacing a Titanium keyboard is a 2-3 minute process, tops.