As reported by IBM on Technote 1252932 under some circumstances the server can crash when you have TNEFEnableConversion=1 in the servers notes.ini file.
According to SPR# DPOS6PVLFC, this error should have been fixed in Domino 7.0.2 Fix Pack 1 (FP1).
Just want to let you know that we had some crashes on our Domino servers yesterday. We have FP1 installed since the day it was available. Looking into the generated NSD Files, we found that the server crashes with exactly the same stacktrace as mentioned in the above technote.
So, be aware when using TNEFEnableConversion=1.