Strange Bug in exim4 postgresql lookup code or libpq?

Hi,

I'm using exim4 together with postgresql.  Sometimes, data lookups fail
mysteriously and on the exim side nobody was able to help.

In short terms: The result code is PGRES_FATAL_ERROR, but the error message
is an empty string.

I opened up a bug in the exim bugzilla:
http://www.exim.org/bugzilla/show_bug.cgi?id=45

The complete description is there and possibly too long for this mailing
list...

Can someone please look at this?  I really need help here :)

Please CC: me on replies, as I'm not subscribed to this list.

Regards,
- Alexander