Question : the specified dhcp client is not a reserved client - error

I get the following error when I try to add a reservation to our dhcp server "the specified dhcp client is not a reserved client"  

Technet reports in this link that my dhcp server appears to be a stand alone
http://technet.microsoft.com/en-us/library/cc976339.aspx

I'm trying to determine if my dhcp server is stand alone and if so why I would want to keep it this way if i can't add reservations?  I didn't set it up and am trying to understand the implications of changing this.

Answer : the specified dhcp client is not a reserved client - error

To determine if your DHCP server is authorised, it's server icon in the DHCP console should have a green upward facing arrow over it when you epand it. Why would you want your DHCP server not authorised? You wouldn't really.

You also get this error message when trying to create a reservation that doesn't fall inside the scope/subnet of the scope you are trying to add it to.

Could you give details of the scope range/subnet and the reservation you're trying to add?