On an openSUSE 12.1 system, fully up to date (LO v.3.4 is latest officially supported) and only under KDE (works fine using GNOME or XFCE).
Open a blank document in writer.
Select mail merge from the tools.
CRASH!
The LO writer dies, no entry in the the process table (no zombie) and nothing particularly informative in any of the /var/log message files.