Acrobat 9 crashes on startup - is it the java, or the fonts, or?

Question

Another MacPro in the room is experiencing crashes on startup of Acrobat 9, which was part of CS5. It was set to bypass the startup screen, so I don't know what it's trying to do when it dies. Here's what I did:
Uninstall, then reinstall. I started it up and it seemed fine: opened files, changed preferences. Then I reinstalled a set of plugins we use from Heidelberg - PDF Toolbox. And I couldn't open Acrobat after that. I remembered we had another problem because the OS was 10.6.x, and Heidelberg claimed that version of Java was too new for the version of their software that we use. We reverted to 10.5.8 for the MacPros that do most of that work. The MacPro with the crashes uses 10.6.8. I thought that a conflict between Java versions might be causing this issue also.
So I uninstalled the plugins, uninstalled Acrobat, used Onyx to clean out caches, rebuild Launch Services and reset permissions; restarted the Mac, reinstalled Acrobat - but it still crashes on startup.
It was working (for quite a while), then it wasn't. It's not my machine so I don't know what changes were made recently. I'd appreciate guidance on what path to take to diagnose this. I've copied the beginning of the crash report below.
Process:         AdobeAcrobat [382]
Path:            /Applications/Adobe Acrobat 9 Pro/Adobe Acrobat Pro.app/Contents/MacOS/AdobeAcrobat
Identifier:      com.adobe.Acrobat.Pro
Version:         9.3.0 (9.3.0)
Code Type:       X86 (Native)
Parent Process:  launchd [96]
Date/Time:       2011-07-07 12:13:57.132 -0700
OS Version:      Mac OS X 10.6.8 (10K540)
Report Version:  6
Interval Since Last Report:          195 sec
Crashes Since Last Report:           1
Per-App Interval Since Last Report:  6 sec
Per-App Crashes Since Last Report:   1
Anonymous UUID:                      FDF375E0-CD77-4C6E-9F94-6079924FF389
Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x000000001798e002
Crashed Thread:  0  Dispatch queue: com.apple.main-thread
Thread 0 Crashed:  Dispatch queue: com.apple.main-thread

Answer 1

Uninstalling and Reinstalling is rarely the best solution. "Nuke and Pave" (erasing your entire drive and starting again) even less so!
The chances are that the application files were installed properly and the fault is not with them. (Well, replacing them with identical copies won't help.)
First thing to do is to delete the preferences relating to Acrobat in <user>/Library/Preferences.
Second thing is to create a brand new user account and test the problem there. If it works fine, then the cause is something in your original user account's Library, such as another preference file or cache. It might also be caused by some Login Items that load at startup in the original user account, which are incompatible in some way.
If the problem still occurs in the new account, then your problem is system-wide, and may relate to a software conflict with some other software. Third-party plug-ins for Acrobat are a good start: remove them and seem if it works.
You will need to look through the entire crash log for clues. References to third-party software; repeated use of terms like USB -- this might give you some indication, so remove that software; remove all peripherals except Apple mouse and keyboard.
Acrobat 9 should work fine on 10.6.8. So there must be something else at work.