How do I prevent FCP crash with divide-by-0 when playing clip?

One of my customers asked if I could modify a clip so that FinalCutPro 7.0.3 could play it without crashing. I've been testing FCP's sensitivity to a number of variables, and finally generated two clips which differ slightly, one of which will crashes FCP (5 times in 5 tries), the other of which doesn't (0 times in 5 tries). The procedure is ...

• Start FCP.
• Add the clip to the project.
• Drag the clip from the project list to the timeline.

For the problem clip, FCP pops up a dialog when adding the clip to the project ("Media Performance Warning ... The following media files are not optimized for Final Cut Pro"). Then, when the clip is dragged to the timeline, there is a 1-2 second pause, and the gui disappears. After another short pause, another dialog appears ("Final Cut Pro quit unexpectedly"), showing a stack dump. See http://www.aratas.org/apple_developer/fcp_crash.txt for the text of both dialogs.

The clips:

• http://www.aratas.org/apple_developer/out_xdcam_09_57_50_19.mov: consistently loads and plays correctly, except that there are 2 black frames at the beginning (I suspect those are due to ctts issues).
• http://www.aratas.org/apple_developer/out_xdcam_09_57_50_20.mov: consistently crashes FCP.

Both of these clips are 4:2:0 25Hz 1080p XDCAM (fourcc "hdv7"). Both use a 12-frame closed-GOP structure with 2 B pictures per I/P picture. out_xdcam_09_57_50_19.mov contains 19 frames; out_xdcam_09_57_50_20.mov contains 20 frames, 19 of which are identical to out_xdcam_09_57_50_19.mov.

Both clips play in these players (no leading black frames in any) ...

• mplayer SVN-r31628-4.1.2 (linux 2.6.18-308.1.1.el5 x86_64)
• mplayer SVN-r30369-4.2.5 (windows 7 ultimate)
• QuickTime Player 10.1 (501.8) (Apple OS X 10.7.3)

I've pretty much exhausted the possibilities I could think of for FCP crashing on the 20-frame file. Any suggestions would be highly appreciated ...