Index: src/main/org/codehaus/groovy/runtime/metaclass/MixinInstanceMetaMethod.java
===================================================================
--- src/main/org/codehaus/groovy/runtime/metaclass/MixinInstanceMetaMethod.java	(revision 16564)
+++ src/main/org/codehaus/groovy/runtime/metaclass/MixinInstanceMetaMethod.java	Thu Nov 12 19:32:03 EST 2009
@@ -33,9 +33,12 @@
     }
 
     public Object invoke(Object object, Object[] arguments) {
-        final Object result = method.invoke(mixinInMetaClass.getMixinInstance(object), arguments);
-        return result;
+        if (method.getNativeParameterTypes().length == 1 &&
+                method.getNativeParameterTypes()[0] == Object[].class) {
+            return method.invoke(mixinInMetaClass.getMixinInstance(object), new Object[]{arguments});
-    }
+        }
+        return method.invoke(mixinInMetaClass.getMixinInstance(object), arguments);
+    }
 
     protected Class[] getPT() {
         return method.getNativeParameterTypes();