Postgres still dying on insert

I have tried almost everything I can think of, put postgres keepy dying.
I am running on a FreeBSD 2.2.5 system. It was complaining about not
enough shared memory. I bumped the shared mem to 16mb (the system has 128)
now it doesn't complain, it just dumps core.
The numbers are different this time, but today, the command I am trying to
execute is:
INSERT INTO word_detail VALUES (131730,18596,1)
now word_detail is:
| word_id                          | int4               | 4 |
| url_id                           | int4               | 4 |
| word_count                       | int2               | 2 |

and it has non-unique indexes on word_id and url_id
sc=> select count(*) from word_detail;
Field| Value
-- RECORD 0 --
count| 637466

There is quite a bit of data here as well...
sc=> INSERT INTO word_detail VALUES (131730,18596,1);
PQexec() -- Request was sent to backend, but backend closed the channel
before responding.
        This probably means the backend terminated abnormally before or
while processing the request.

No debugging comes out in the log either:
FindBackend: found "/usr/local/pgsql/bin/postgres" using argv[0]
        ---debug info---
        Quiet =        f
        Noversion =    f
        timings   =    f
        dates     =    Normal
        bufsize   =    256
        sortmem   =    4096
        query echo =   t
        DatabaseName = [sc]
        ----------------

        InitPostgres()..
        StartTransactionCommand() at Mon Apr 27 19:46:41 1998

        ProcessQuery() at Mon Apr 27 19:46:41 1998


I even tried selecting this into another table and re-building the
indexes.

It allowed me to insert about 50 more values in before it started crapping
out again. Any ideas? The binaries compiled normally and passed all the
tests.

-Mike