If you receive this error message it is because you are entering data onto an empty record, to correct this you will need to do the following:
Go to Enquires and then Contacts Database
Select the type of contact you want to add: Subcontractors, Suppliers, Professionals or Clients
Click add new
Enter a code - this must be a Unique code.
Once the record is created the edit function will allow you to enter the details.