Unable to Login Locally

I am unable to login locally to either a BDC or PDC of a domain. I do not get the drop down menu to allow login to the local machine. When I try to change the domain to local machine I get the message: "this machine is a member of X domain focus will be set in the X domain". Is this normal? Does only a member server allows this option?. Any help will be gratly appriciated Thanks in advance.

I think you have to log into the domain the workstation is set to and then once in add the computer to the other domain .

You can't log into the local machine of a domain controller, since it is a domain controller the local machine is the domain. To log on to a domain controller you must be an administrator of the domain.