FM9 crash during show/hide of conditional text

Question

I'm having a vexing problem with two of my chapters: whenever I attempt to show/hide the conditions, FM9 crashes with "Internal Error 9004, 6921852, 9677150, 0. Framemaker has detected a serious problem and must quit".
A few things I've tried (as culled from posts on here):
Updating to FrameMaker p250 from p237
Saving as .mif, then opening and saving as .fm
Changing the conditions on all chapters with the book open
It's somewhat unpredictable. Saving as a .mif, then opening and saving as .fm worked once, but after performing an edit to the doc, it crashed again when toggling the conditions. Similarly, changing the conditions to all chapters with the book open seemed to avoid a crash, but trying it again crashed when it reached the problem chapter.
It's definietly something in the file, as my co-worker will occasionally get the crashes with the the same chapters when showing/hiding conditions, but not always.
Other details:
My XP installation is up to date with all the Microsoft updates
I'm using FM9 (unstructured)
The docs in question are not "fresh" per se, but have been upgraded from FM8 to FM9
Also:
Our documents have conditions A, B, C, and D.
In previous versions of Frame, we had been using the shuttle box interface for showing/hiding conditions: show A and B, hide C and D.
Starting with FM8, we started using equivalent logical expressions: NOT "C" AND NOT "D".
The crashing appears *not* to occur if I use the shuttle box interface. However, I'm told that we have use the logical expressions for some reason.
Any ideas are appreciated. Thanks!

Answer 1

SOLVED
Here's my fix for Internal Error: 9004, 6921852, 9677150, 0 when saving as PDF, printing PDF, or printing to PS from FrameMaker 9 using Acrobat 9. YMMV.
I could not reproduce this  Internal Error: 9004, 6921852, 9677150,0 when using conditions, so I do not know if this solution fixes the condition-provoked instance of  Internal Error: 9004, 6921852, 9677150, 0.
Anyway, I uninstalled FM, rebooted, searched for leftover files, deleted them, rebooted, uninstalled Acrobat Pro Extended 9, searched for leftover files and registry entries, deleted them (probably missed a few), rebooted, removed the Xerox Phaser PS printer driver for my local printer (because it was PostScript, figured I should), rebooted, installed the Xerox Phaser PS driver, rebooted, installed FrameMaker, rebooted, installed Acrobat Pro Extended 9, rebooted, installed each patch for FrameMaker and Acrobat Pro Extended 9, rebooted, installed the MS Hotfix discussed here (http://blogs.adobe.com/techcomm/2008/07/hotfix_for_framemaker_1.html), and rebooted.
All is now well for making PDFs.
Sean