diff --git a/app/models/report/operator.rb b/app/models/report/operator.rb
index 65461c5cd0..1a05c7f862 100644
--- a/app/models/report/operator.rb
+++ b/app/models/report/operator.rb
@@ -240,9 +240,9 @@ class Report::Operator
     validation_methods = values.delete(:validate)
     register_validations(validation_methods) unless validation_methods.nil?
     values.each do |key, value|
-      metaclass.class_eval { define_method(key) { value } }
+      singleton_class.class_eval { define_method(key) { value } }
     end
-    metaclass.class_eval(&block) if block
+    singleton_class.class_eval(&block) if block
   end
 
   def to_operator
@@ -280,4 +280,4 @@ class Report::Operator
   # Done with class method definition, let's initialize the operators
   load
 
-end
\ No newline at end of file
+end
diff --git a/app/models/report/validation.rb b/app/models/report/validation.rb
index 4e3655e281..a4d0b7dc96 100644
--- a/app/models/report/validation.rb
+++ b/app/models/report/validation.rb
@@ -9,7 +9,7 @@ module Report::Validation
     const_name = val_method.to_s.camelize
     begin
       val_module = Report::Validation.const_get const_name
-      metaclass.send(:include, val_module)
+      singleton_class.send(:include, val_module)
       val_method = "validate_" + val_method.to_s.pluralize
       if method(val_method)
         validations << val_method
@@ -40,4 +40,4 @@ module Report::Validation
     end
   end
 
-end
\ No newline at end of file
+end