tsearch2 and unexpected exists

This will be a little vague, it was last night and I can't now do the test in
that db (see below) so can't give the exact wording.

I seem to remember a report a little while ago about tsearch v2 causing
unexpected backend exit messages with 7.3.4 and now I'm getting similar
messages unpredictably and I can't find the thread in the archives either.

What I did was install tsearch2 using share/contrib/tsearch2.sql, which placed
everything into public schema. Having created the tsvector column in a table
and populated it I tried running a pretty simple function that queried that
table (joined with another) using that tsvector column in the where
clause. This gave the unexpected exits of the backend (only the one for that
connection not all). The error was something like invalid MemoryContext
allocation 0. Other attempts gave a large number instead of 0. However, the odd
thing is that the query from the function that was using tsearch2 worked
fine when I cut it from the log and pasted it into psql directly.

The function is in plpgsql, this is the stable tarball of tsearch v2 for 7.3.4
and obviously the server is 7.3.4. All running on Debian linux (woody).

Unfortunately I can't reproduce this problem without reinstalling the db, or
seeing if createlang will work, since the untsearch2.sql script failed (I was
trying to reload tsearch2.sql jsut to see) so I foolishly dropped public schema
since I stupidly thought tsearch was the only thing using it. More importantly
I don't seem to be able to find the mailing list thread that covered pretty
much this exact unexpect exit fault. So, can anyone help with a fix,
explanation or link to the relevent thread please?

Thanks,

--
Nigel J. Andrews