Mike,
Did this happen after upgrading from V11.5 to V11.6.x??
If so then you should know that the LDAP config is now in the UI. Make sure that you verify the Group Directory Credential section in the System Settings. This is where the Upgrade is now storing the credentials.
Verify that the connection still works. You may need to adjust the BaseDN settings to make sure that it is correct. Also make sure that the BaseDN is correct.
Also veriy the LDAP plugin setting to make sure that you rearrange the order of the lookup that happens. During the upgrade the LDAP lookup order is re-arranged. (Bad)
Send some screen shots and let me see if I can help again
Here are some of my other instructions:
https://www-secure.symantec.com/connect/forums/dlp-116-liveldaplookup
https://www-secure.symantec.com/connect/forums/configuring-ldap-custom-attributes
Please call this solved if I answered your questions