Reinstall and Install horrors

Question

Earlier this month Time Machine crashed during a backup and hung the system. Then I could not reboot. I booted from TechTool 4 and attempted to repair the drive, but it couldn't be repaired. I booted from the Leopard DVD and ran Disk Utility and it too said the drive could not be repaired - it said there were keys out of order and the leaf count was wrong among a slew of other problems. Also, all backups except for the one done the night before were gone - 6 months worth. After much hand-wringing I performed a restore off the last remaining backup. It ran for 4 hours and finally restored.
All was fine for a few days and with backups working fine. Then another bad crash - just like the first. Tried to repair with DU and Techtool but no luck. So, I did another restore but that failed at 98% into the restore. Tried it again and got the same problem about 60% into the restore. I was using the latest backup (4 days after the first restore. Thinking that there was corruption in that restore I used the oldest BU - the one I used initially - but this also failed. Tried numerous times - it took days but each time failure, So, I then wiped the problem drive clean and attempted to reinstall 10.5 from the DVD. It got about 75% complete and failed - hung. I started all over again - erased the drive, zeroed it out and tried again - this time after about 20 minutes failed again saying that the "Installer could not validate the contents of the BaseSystem" Tried again - I did do the verification of the DVD first and BTW I have had Leopard (10.5.3) running on this machine for months with no problem. Each time I attempted an install I got the same message "Installer could not validate the contents of the BaseSystem", So, thinking it might be the hard drive I installed a new HD to no avail - same problem. I then took another copy of the Leopard install disk I have and had the same problem. So, I got a new optical drive and tried that and it failed the same way,
My G4 PPC MDD has 3 drives in it and I have another installation of 10.5.4 on one of the drives so I was resigned to having to pull all of my files and apps from the Time Machine backup onto this drive, but other problems started. All of the 3rd party apps would not launch - Photoshop, word, appleworks, etc. and I could not do a fresh install either - the installers will not launch. Console reported that the binary files could not be executed.
Looking through the various Console messages I noticed a hugh amount of info.plist errors among a slew of others and then this installation started to behave really weird. Sometimes starting up fine then hanging or crashing. Disk Utility or techtool were able to repair the volumes but then it would happen again. After days of this (lucky I have a few other Macs to use) and much checking of the various useful Apple help spots I decided that I would reinstall the 10.5.4 combo updater. No luck - it too hung just like others are describing in this thread. Further, I removed all 3rd party memory and a USB 2.0 card I had installed but this did nothing.
I am at my wits end - if I could either repair or reinstall 10.5.4 or do a clean install of Leopard on another drive I could get all back in order as no data has been lost. Any help would make my day. Also, would Disk warrior be a better choice to do these type of repairs?
Thanks

Answer 1

I upgraded my copy of Disk Warrior and it indeed fixed a lot of problems. As far as I can determine there is RAM problem - a serious one.
When I initially ran the Apple Hardware Test it would not launch saying that there was an Invalid Memory Access. So, I removed the memory and added each of the 4 modules back in one by one. Only of module out of the four was okay enough for the hardware test app to launch. It tested fine. I then added the other modules back in one by one with the good module. One of them did allow the test to launch, but it failed with the extended test. The others, when installed with the good one prevented the test launch giving the Invalid Memory Access notification again.
Interestingly, the G4 will boot normally into 10.5.4 when all are installed, but flakiness does continue especially running Disk Warrior on corrupt drives.
Further all of the 4 modules have been in use from 4 years to 7 months and the machine has performed fine. I suspect that the problem is somehow related to the latency set on these various modules all from different vendors that is causing a sync problem once the memory is heavily stressed. The CL on the one good module is as follows: CL: 5, CL3: 6.0, CL2 7.5
I am a bit surprised that 3 modules would be bad. I guess I now have to go through the hassle of returning the defects as they all have lifetime warranties. Sigh.