Postgres logs behind 500 error

postgresql-8.4-main-excerpt.log

2011-07-08 15:03:00 CDT ERROR:  GEOS Intersection() threw an error!
2011-07-08 15:03:00 CDT STATEMENT:  SELECT rd.id,
        rd.district_id,
        rd.name,
        rd.is_locked,
        lmt.version,
        rd.plan_id,
        rc.subject_id,
        rc.number,
        st_asgeojson(
            st_intersection(
                st_geometryn(rd.simple,3),
                    st_envelope(
                        ('SRID=' || (select st_srid(rd.simple)) || ';LINESTRING(-9973220.566558 4783356.2731
40,-8432250.076605 5010832.869276)')::geometry
                    )
                )
            ) as geom ,
        rd.num_members
        FROM redistricting_district as rd 
        JOIN redistricting_computedcharacteristic as rc 
        ON rd.id = rc.district_id 
        JOIN (
            SELECT max(version) as version,district_id
            FROM redistricting_district 
            WHERE plan_id = 90 
            AND version <= 0 
            GROUP BY district_id) 
        AS lmt 
        ON rd.district_id = lmt.district_id 
        WHERE rd.plan_id = 90 
        AND rc.subject_id = 18 
        AND lmt.version = rd.version 
        AND st_intersects(
            st_geometryn(rd.simple,3),
                st_envelope(
                    ('SRID=' || (select st_srid(rd.simple)) || ';LINESTRING(-9973220.566558 4783356.273140,-8432250.076605 5010832.869276)')::geometry
                )
            ) AND NOT rd.name = 'Unassigned'
2011-07-08 15:03:00 CDT ERROR:  current transaction is aborted, commands ignored until end of transaction block
2011-07-08 15:03:00 CDT STATEMENT:  SAVEPOINT s140186118670080_x1