With the samba-3.0.23 and 3.0.23a releases, in my logs the error "smbldap_open: cannot access LDAP when not root.." is very frequent (several times per minute).
The server is a Gentoo i686, domain PDC and wins master browser, linked with openldap-2.2.28.
Ldap is on an external server (same lan).
log is always like:
smbd [pid]: [<date>, 0] lib/smbldap.c:smbldap_open(1009)
smbd [pid]: smbldap_open: cannot access LDAP when not root..
Please try the LocalGroups patch at http://www.samba.org/samba/patches/.
If that does not fix it, then I need level 10 debug logs from smbd.
please reopen if the referred topatch does not solve the issue.