samba - Apr 2007 - winbind's libads/ldap_utils.c repeatedly says 'failed to reconnect (Timed out)'

I'm repeatedly needing to restart winbind v3.0.22 on ubuntu server
v6.10.  The reason why is that it fails to get group info.  The passwd
info is still accessible; it just can't figure out what groups a person
is in.  I'm using idmap backend = ad , and winbind nss info = sfu.

Looking in /var/log/samba/log.wb-ADDOMAINNAME, I see many lines at
seemingly randomly time intervals that read like this:

[2007/04/30 04:30:16, 1] libads/ldap_utils.c:ads_do_search_retry(77)
  ads_search_retry: failed to reconnect (Timed out)

Are these lines related to my need to restart winbind?  Either way, are
they indicative of a problem that should be fixed?  If so, any idea how
to fix the probem?

Thanks,

Jon

Relevant smb.conf directives follow:

        security = ADS
        socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192
        os level = 99
        preferred master = No
        local master = No
        dns proxy = No
        idmap backend = ad
        idmap uid = 500-45000
        idmap gid = 500-45000
        template homedir = /home/%U
        template shell = /bin/bash
        winbind separator = +
        winbind cache time = 600
        winbind use default domain = Yes
        winbind nested groups = Yes
        winbind nss info = template, sfu
        invalid users = root