sounds like your TTP and DW disks are not compatible with that G5. what version of TTP and DW are you trying to use on this machine? there are very few old versions of either one that will work on your new intel G5.
also, from your log file the Verbatim drive is failing.
To make sure your G5 is not too upset about accessing that failing drive so often: Start up your G5 holding the shift key down until you see the login screen. YOu should see SAFE MODE on the top of the window. Log in and goto your utiilities folder and run Disk Utility, repair permissions and then verify the disk. if either one comes up with errors you need to invest in a new copy of TTP5. or
If you have the system (grey) disks that came with the machine. Start up with the 1st disk in the machine and hold the option key down. you should see both your HD/OS and DVD/OS and be able to select the DVD install disk. If this is your first time doing this, it will appear that you are trying install the os again. this is normal, get past the keyboard language selection and then go to the utilities within the menu, you should see disk utility. Run the disk repair first and repair permissions twice after that. Quit out of everything and allow your machine to restart. This should make your machine really happy. hope this helps.