please do NOT replye / hijack old threads.
Your problem looks like you’re using an OpenLDAP ObjectClass (posixAccount) with an ActiveDirectory server.
Anyway just switching Account and Authentication from SQL to LDAP, will break you EGroupware Installation as the numerical IDs used in the database no longer match.
If you only want Authentication, do NOT switch Accounts to LDAP, it means users, groups and group-memberships are no longer stored in the database, but read from the LDAP server. Just Authentication is more simple, it only requires users with identical user-names exist in your directory.
If you use a ActiveDirector server, it’s a lot easier to configure it as ActiveDirectory in EGroupware, than using the LDAP configuration for it. Just using Authentication (and not Accounts) applies equally.
I recommend we have an other call discussing your LDAP / ActiveDirectory strategy. Nowerdays I almost always recommend to use a periodic account import, over storing accounts in LDAP/AD.