Ah, sorry about that. It's what happens when I post in frustration at 5:00 in the morning. But thanks for the response.
Windows 7 64-bit
Premiere Pro 5.5.1
Combined Community Codec Pack
K-Lite Codec Pack
Not sure if Mercury Playback is enabled. The crash only happens when creating a file in Media Encoder. I've isolated the problem to rendering as a DVD-Mpeg with "Render at Maximum Depth" checked. When it is unchecked, the files render without a crash.