pgReadData error on simple selects

I'm getting the following error message when I try and execute:
'select name from chapter where path ~ 'glacier/$';'

pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.

I changed my code to keep reusing the same PGconn rather than reconnecting
for each query (which is what worked before) as I believe it will be
faster. The above error manifests itself after about the 5th query. I'm
using v1.18 of the Pg library for v5.005_03 of Perl and v.7.0.2 of
Postgresql. I can't find release notes for v7.0.3 to see if this is
addressed (I doubt it) when I look at
http://www.postgresql.org/docs/admin/. I can't find anything in the
Programmers Guide that seems to address this and the web search interface
to the mailing list archives sucks.

any suggestions?

--sam