Target Disk Mode not working

[zippy2]

I'm trying to transfer some programs from a recently purchased G4 to my iMac using Target Disk Mode. If I try to start by holding down the "T" the computer starts just like normal, no grey fireware logo, just the normal desktop. I have also tried to restart the computer in Target Disk Mode going through system preferences. This doesn't work either and after this it will only start if I hold down Apple, Option, P & R keys. Any suggestions? Could there be something wrong with the computer? I bought it from someone sight unseen and I'm wondering if it is a lemon or if I am doing something wrong. I need to get some software off of it to my current iMac.