"duplicate key violates unique constraint" error

Hi All

I have a cluster setup with one master and one slave . Replication from
master to slave is not taking place.

I am getting this error "duplicate key violates unique constraint" in
my slon.log on slave . This error is thrown while

Slon is inserting a row in a table on slave. This must be because of
the reason that duplicate rows

are being returned while querying sl_log_1 table. I googled about the
same problem and found that

there is some bug in postgres due to which some table or index on that
table gets corrupted. Due to this

duplicate rows are either stored in the table or there are no duplicate
rows but

duplicates are returned while querying the table.

I am using postgres 8.1.2 and slony 1.1.5 .

Please suggest which version of postgres has fix for above mentioned
problem.

Thanks...

Tamanna