Idle in transaction connection

Hi all

I have a Postgresql 8.2.10 install running on w2k3, and recently, or
more precisely, after I upgraded from 8.2.5 to 8.2.10,
some connections keep in the 'idle in transaction' state. The real
problem is that even after I kill the connection subprocess,
the pg_stat_activity reports that the connection is still there, and the
locks too. The only thing that solves this is restarting Postgres.
Any clues of what might be happening?

Thanks for tha attention.