Cache lookup error

Hi,

I am new to user lists, so please don't be to hard on me if I am doing
anything wrong.

I have been running a postgres database with slony replication for some
years now as a backend for a apache webserver and lately some mono
(.net) programs. The database and webserver is running on a Ubuntu LTS
server and I compile the programs myself to be reasonable updated.

Current version is postgres 8.3.7 and Slony1-2.16

Yesterday I got a lot of errormessages in the postgres log.

2009-11-12 06:11:51 CET INSERTERROR: cache lookup failed for type 19218
2009-11-12 06:11:51 CET INSERTCONTEXT: SQL statement "INSERT INTO
_slony_webtrim.sl_log_1 (log_origin, log_xid, log_tableid,
log_actionseq, log_cmdtype, log_cmddata) VALUES (1, $1, $2,
nextval('_slony_webtrim.sl_action_seq'), $3, $4);"
2009-11-12 06:11:51 CET INSERTSTATEMENT: INSERT INTO reservation1
(activityid, activitydate, clientno, deptno, reservations, activityname,
room, dayofweek, starttime, maingroupname, activitystartdate,
activityenddate) SELECT activityid, '2009-11-12' AS activitydate,
clientno, deptno, 1 AS reservations, activityname, room, dayofweek,
starttime, maingroupname, activitystartdate, activityenddate FROM
activity WHERE activityid = 5374

2009-11-12 06:27:48 CET UPDATEERROR: cache lookup failed for type 19218
2009-11-12 06:27:48 CET UPDATECONTEXT: SQL statement "INSERT INTO
_slony_webtrim.sl_log_1 (log_origin, log_xid, log_tableid,
log_actionseq, log_cmdtype, log_cmddata) VALUES (1, $1, $2,
nextval('_slony_webtrim.sl_action_seq'), $3, $4);"
2009-11-12 06:27:48 CET UPDATESTATEMENT: UPDATE reservation2 SET
datetimereceipt = '2009-11-12 06:27:48' WHERE clientno = 342 AND refno =
945005

The applications worked happily as if everything were ok, but the data
was never written to disk and is lost. The error came after I dropped
(cascade) the slony schema and reinstalled it. I were not able to dump
the database (just hanging), but dumping table by table went ok. After
reinstalling the database (initdb) and install slony, everything seems
ok. I have scripts for installing slony, so there should not be any
differences in the way it is done.
I have had a database error once before, also after reinstalling slony.

I would appreciate very much if someone could tell me what kind of error
this is, and maybe some hints so I might avoid it in the future.

Best regards
Gunnar