Microsoft Exchange Server 5.5 problem

Hi,

If I log into a Microsoft Exchange Server 5.5 server as the domain administrator, i can run the Microsoft Exchange Administrator program. If I log into the same server as a domain user who is a member of the local administrators group, I will get the error DS_E_INSUFFICIENT_ACCESS_RIGHT when I try to run the Microsoft Exchange Administrator program. I want someone, who does not belong to domain administrator, can run the Microsoft Exchange Administrator program.

Thank you.