Leopard 10.5.7 refuses to launch applications after "erase and install"

Question

I have an older iMac G5 (1.6Mhz PPC, 2 Gb RAM) born with Panther OS. I wanted to update some applications so I could have a secure browser and other apps. I upgraded the RAM to 2 Gb as a first step. The additional RAM really perked up the old iMac so the next step was to update the OS to 10.5.6 using a DVD that was printed in Jan '09 and sold as part of a bundle pack with the new iLife 09 and iWork 09.
I thought I could get away with an overwrite installation and I knew there were risks in doing that. The result was a really bugey computer with frequent terminal views, kernel panics and even hard shut downs. Apple issued the 10.5.7 update and that helped stabilize the system somewhat.
I still had problems with instablility of the OS and with Safari 3.2.3, Firefox 3 and other applications. I decided to reinstall Leopard using the archive and install procedure. The 2nd install stabilized the OS but I still had problems with browsers and Open Office refusing to launch.
I did lots of troubleshooting using Onyx, MemTest OSX, repair permissions in the Disk Utility, etc. I created a new user account and the problems persisted. I decided to try a third install of the OS using the Erase and Install procedure.
The system now has Safari 4.0.1 but after a few page views Safari crashed and now it crashes as soon as you launch it. A freshly downloaded Camino browser does the same thing. iTunes, System Profiler and a fresh download of Onyx also refuse to launch. All of them crash while launching.
I can launch an ancient version of IE and Firefox 3 from the desktop.
After the last OS X install, I noticed the system did not accept the first attempts at downloading the Leopard updates and the Safari update. A second attempt was successful for both. I am reluctanct to proceed with installing anymore applications until I can fix what I believe is a problem with the OS. The OS worked well after the archive and install procedure and I am thinking it should be able to work at least as well after the erase and install.
I live in a rural area and the nearest Apple "genius" counter is about a 5 hour round trip. Is there anyone out there that has encountered this problem?

Answer 1

The Internet Explorer came with the iMac and I never used it. I had it on a disk so I put it on the desktop to get a download of Camino after Safari failed. It's so old that most websites can't render for it unless they have some html default page.
Here is what the Crash Reporter log had. The iTunes was on the OS X install disk. The Camino browser was downloaded from Caminobrowser.org.
Process: iTunes [275]
Path: /Applications/iTunes.app/Contents/MacOS/iTunes
Identifier: com.apple.iTunes
Version: ??? (???)
Build Info: iTunes-8202301~15
Code Type: PPC (Native)
Parent Process: launchd [67]
Date/Time: 2009-07-04 21:34:25.644 -0700
OS Version: Mac OS X 10.5.7 (9J61)
Report Version: 6
Anonymous UUID: 17FE9D2E-ED3C-44C8-BD16-23C937CA83AE
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000001, 0x000000008fe0105c
Crashed Thread: 0
Dyld Error Message:
Symbol not found: __ZN7WebCore11RenderLayer18gAlignCenterAlwaysE
Referenced from: /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit
Expected in: /System/Library/Frameworks/WebKit.framework/Versions/A/Frameworks/WebCore.frame work/Versions/A/WebCore
Process: Safari [118]
Path: /Applications/Safari.app/Contents/MacOS/Safari
Identifier: com.apple.Safari
Version: ??? (???)
Build Info: WebBrowser-55301800~1
Code Type: PPC (Native)
Parent Process: launchd [67]
Date/Time: 2009-07-04 21:14:45.039 -0700
OS Version: Mac OS X 10.5.7 (9J61)
Report Version: 6
Anonymous UUID: 17FE9D2E-ED3C-44C8-BD16-23C937CA83AE
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000001, 0x000000008fe0105c
Crashed Thread: 0
Dyld Error Message:
Symbol not found: __ZN7WebCore11RenderLayer18gAlignCenterAlwaysE
Referenced from: /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit
Expected in: /System/Library/Frameworks/WebKit.framework/Versions/A/Frameworks/WebCore.frame work/Versions/A/WebCore
Process: Camino [361]
Path: /Volumes/Camino/Camino.app/Contents/MacOS/Camino
Identifier: org.mozilla.camino
Version: ??? (???)
Code Type: PPC (Native)
Parent Process: launchd [67]
Date/Time: 2009-07-04 22:14:43.753 -0700
OS Version: Mac OS X 10.5.7 (9J61)
Report Version: 6
Anonymous UUID: 17FE9D2E-ED3C-44C8-BD16-23C937CA83AE
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000001, 0x000000008fe0105c
Crashed Thread: 0
Dyld Error Message:
Symbol not found: __ZN7WebCore11RenderLayer18gAlignCenterAlwaysE
Referenced from: /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit
Expected in: /System/Library/Frameworks/WebKit.framework/Versions/A/Frameworks/WebCore.frame work/Versions/A/WebCore