I am getting the mentioned error in the following line:
map1.get(PAPC.Country__c).Q1__c += (PAPC.Q1FX__c == null ? 0.0 : PAPC.Q1FX__c);
Baically it's assigning value from one object to the other.
Q1FX__c can be zero at times .
Please help me understand why the error , since I'm encountering it for the first time.