[CentOS] Problem with CentOS 4.3 and ldap

I currently have a server with centos 4.3 setup to do email.  I use
sendmail as the receiving agent and Dovecot as the pop/imap server.  Users
authenticate off of a openldap server.  Under a light load things appear
to work fine.  However under a moderately heavy load connections are left
open in a waiting state.  This causes some email to bounce with user
unknown, users authentications fails with bad username/password all with
valid accounts.

I am trying to figure out what the cause is to fix it but with out
success.  By restarting ldap and the ldap server I can minimize the
problem because the connections get reset.  I find nothing when I google
on the subject.  I don't believe this is a problem with the ldap server
because I have a Fedora core machine using it without problems.

Any help or ideas on how to track down the problem would be appreciated.

Myron Williams