diff --git a/Source/Ejecta/EJUtils/EJBindingGameCenter.m b/Source/Ejecta/EJUtils/EJBindingGameCenter.m
index 8c862096..6d2be280 100644
--- a/Source/Ejecta/EJUtils/EJBindingGameCenter.m
+++ b/Source/Ejecta/EJUtils/EJBindingGameCenter.m
@@ -232,13 +232,14 @@ - (void)reportAchievementWithIdentifier:(NSString *)identifier
 
 
 #define InvokeAndUnprotectCallback(callback, error, object) \
+	JSContextRef _gctx = scriptView.jsGlobalContext; \
 	[scriptView invokeCallback:callback thisObject:NULL argc:2 argv: \
 		(JSValueRef[]){ \
-			JSValueMakeBoolean(scriptView.jsGlobalContext, error), \
-			(object ? NSObjectToJSValue(scriptView.jsGlobalContext, object) : scriptView->jsUndefined) \
+			error ? NSStringToJSValue(_gctx, error.localizedDescription) : JSValueMakeNull(_gctx), \
+			(object ? NSObjectToJSValue(_gctx, object) : scriptView->jsUndefined) \
 		} \
 	]; \
-	JSValueUnprotect(scriptView.jsGlobalContext, callback);
+	JSValueUnprotect(_gctx, callback);
 
 #define ExitWithCallbackOnError(callback, error) \
 	if( error ) { \