Setting User Permissins In A Workgroup.

I have three xp pro workstations, all are networked and sharing a cable connection.  I have Diskeeper 7.0 server installed on one of these three.  I\'m trying to do remote installations two the other two from this "server" but  it fails cause "no proper permissions set"  this has to be because i do not have workgroup wide user logins - each computer has its own login.

Is there a way to set users up that can login the workgroup.  

hope i explained myself.