attemt to de-reference a null object

trigger PopulateRegion on Shipment_Order__c (after insert, after update) {
for(Shipment_Order__c shipmentorder : Trigger.new) {
If(shipmentorder.Hub_Shipment_Formula__c == False ){
        string region = Country_Region_List__c.getInstance(shipmentorder.Ship_From_Country__c).Region__c;
        shipmentorder.Ship_From_Zone1__c = region; 
}
    Else { 
    string region3 = Country_Region_List__c.getInstance(shipmentorder.Ship_From_Country__c).Region__c;
    string region2 = Country_Region_List__c.getInstance(shipmentorder.HUB_Country_Formula__c).Region__c;
    shipmentorder.Ship_From_Zone1__c = region3;
    shipmentorder.Hub_Ship_From_Zone__c= region2;
}
}
}