Entourage 2004 and Exchange

Hello, I would like to ask someone if can help me with problem I am facing 3 days. I have MacBookPro with installed OS X 10.4. E-mail client is Microsoft Entourage 2004 (version 11.3.2 build 061213). On the server side is Microsoft Exchange 2003 (6.5.7638.1). I setup the Entourage for Exchange account and my e-mail work. I can send and receive. Problem is with Global Address List (GAL). I always get error: Entourage cannot connect to the server. Verify that your computer is connected to the network. Error -3260 after repairing Entourage database I can see all suboffices, but when I click to get users from any suboffice i got: An unknown error (-17768) occured: LDAP Server Error Background: I did a little research what's going on so... Exchange computer is connected to the network. I have remote access (via Terminal Services) so I am 100% sure it is working. I triend PING - working. I tried TELNET to ports 25, 80, 110, 389 - every port reply, every connection was established. I tried also connect via Outlook Web Access (via Safari browser) and it works (including searching in Global Address Lists). I am not sure, but just in case, I haven't activated Active Directory and LDAPv3 in Directory Access (but from my point of view it doesn't make difference). I haven't also anything typed in searchbase. Thank you very much in advance for any help regarding this issue.