diff --git a/qubesmgmt/exc.py b/qubesmgmt/exc.py
index 347c5f0..053bfef 100644
--- a/qubesmgmt/exc.py
+++ b/qubesmgmt/exc.py
@@ -25,4 +25,6 @@ class QubesException(Exception):
     '''Base exception for all Qubes-related errors.'''
     def __init__(self, message_format, *args, **kwargs):
         # TODO: handle translations
-        super(QubesException, self).__init__(message_format % args, **kwargs)
+        super(QubesException, self).__init__(
+            message_format % tuple(int(d) if d.isdigit() else d for d in args),
+            **kwargs)
diff --git a/qubesmgmt/tests/errors.py b/qubesmgmt/tests/errors.py
index b9ae736..b72da65 100644
--- a/qubesmgmt/tests/errors.py
+++ b/qubesmgmt/tests/errors.py
@@ -39,7 +39,6 @@ class TC_00_Errors(qubesmgmt.tests.QubesTestCase):
         self.assertEqual(str(context.exception),
             'An error occurred: string, other')
 
-    @unittest.expectedFailure
     def test_002_exception_with_numbers(self):
         self.app.expected_calls[('dom0', 'mgmt.vm.List', None, None)] = \
             b'2\x00QubesException\x00\x00' \
@@ -49,7 +48,7 @@ class TC_00_Errors(qubesmgmt.tests.QubesTestCase):
                 vms = list(self.app.domains)
         except TypeError as e:
             self.fail('TypeError: {!s}'.format(e))
-        self.assertEqual(str(context.exception), 'An error occurred: 1 2')
+        self.assertEqual(str(context.exception), 'An error occurred: 1, 2')
 
     def test_010_empty(self):
         self.app.expected_calls[('dom0', 'mgmt.vm.List', None, None)] = b''\