Added a space to the message

Author: ThomasWunderlich

library/Zend/Json/Server.php

@@ -550,7 +550,7 @@ protected function _handle()
                     $orderedParams[ $refParam->getName() ] = $refParam->getDefaultValue();
                 } else {
                     throw new Zend_Server_Exception(
-                        'Method ' . $request->getMethod() .  'is missing required parameter: ' . $refParam->getName()
+                        'Method ' . $request->getMethod() .  ' is missing required parameter: ' . $refParam->getName()
                     );
                 }
             }