diff --git a/lib/xmlenc/builder/base.rb b/lib/xmlenc/builder/base.rb
index b5e9eed..e1f3e33 100644
--- a/lib/xmlenc/builder/base.rb
+++ b/lib/xmlenc/builder/base.rb
@@ -31,7 +31,7 @@ def from_xml?
 
       module XmlMapperClassMethods
         def parse(xml, options = {})
-          raise Xmlenc::UnparseableMessage("Unable to parse nil document") if xml.nil?
+          raise Xmlenc::UnparseableMessage.new("Unable to parse nil document") if xml.nil?
 
           object = super
           if object.is_a?(Array)
diff --git a/spec/lib/xmlenc/builder/base_spec.rb b/spec/lib/xmlenc/builder/base_spec.rb
index 5f99765..0ae6a78 100644
--- a/spec/lib/xmlenc/builder/base_spec.rb
+++ b/spec/lib/xmlenc/builder/base_spec.rb
@@ -21,7 +21,7 @@ class BaseDummy
     it "raises an error if the message is nil" do
       expect {
         BaseDummy.parse(nil)
-      }.to raise_error(Xmlenc::UnparseableMessage)
+      }.to raise_error(Xmlenc::UnparseableMessage, 'Unable to parse nil document')
     end
   end
 end