Hi,

You might have deleted the field from the view either using the custom module or by editing the view from the front end by activating the developer mode. You can understand this by looking at your database.

If you have replaced the field using a custom module, you can uninstall the module. If the field is replaced by editing the view from the front end, activate the developer mode and open the corresponding form and click the debugger button near the logged in users name and click the Edit Form View button and check whether you can see a field named country_id in the architecture or in the inherited views. If field is existing check whether there is a invisible="1" attribute along with the field, if exist change it to invisible="0" .

if you don't want to loose time for searching the above, you can directly add a field to the view by activating  the developer mode, see this: Add Field to the View

Thanks