DBI not disconnecting

I'm building a chat room and having a problem with the MySQL interface not l
etting go of a connection no matter how many disconnect instructions we give
 it. The DBI connection line looks like this:

$dbh = DBI->connect($dbi_dsn, $dbi_user, $dbi_password, { AutoCommit => 1, R
aiseError => 1, PrintError => 1 });

I've tried setting the AutoCommit to 0, but that just broke everything. I'm 
not real great with Perl and I haven't been able to figure out which of the 
hundreds of DBI connections is refusing to close, though I think I've narrow
ed it down to just over a dozen. Can anyone give me some advice on how to fi
x this?