Unable to "Add Address" in Phonebook

I have recently changed my work PC from a desktop to a laptop. All my softare and data was migrated across to my new machine and went reasonably well.

However, in Lotus Notes, I have lost the functionality of being able to add a name from the company Directory to my personal address book. For some reason the little add button is grayed out. Prior to changing my PC, this function worked perfectly.

Has anyone any suggestion on how I can re-enable this button? Thanks