         if (g11nWorkingInstance)
             return g11nWorkingInstance.getMonthNames(nameStyle, context);
 
-        if (!localeStyle)
+        if ((localeStyle === undefined) || (localeStyle === null))
         {
             fallbackLastOperationStatus
                                 = LastOperationStatus.LOCALE_UNDEFINED_ERROR;

        if (g11nWorkingInstance)
            return g11nWorkingInstance.getFirstWeekday();

        if (!localeStyle)
        {
            fallbackLastOperationStatus
                                = LastOperationStatus.LOCALE_UNDEFINED_ERROR;


    public function set dateStyle(value:String):void
    {
        if(dateStyleOverride != null && dateStyleOverride == value)
            return;
        dateStyleOverride = value;

        if (g11nWorkingInstance)
