problem with dbus execution

Hi,

I have runned an application, on the robot MarXbot, that call these 2 functions in the same time and wait for their replies. 

First function:
QDBusConnection connection = QDBusConnection::systemBus();
 ch::epfl::mobots::AsebaNetwork network(DBUS_SERVICE_ASEBA, DBUS_PATH_ASEBA, connection);
 QDBusPendingReply<Values> reply = network.GetVariable("base-sensors","proximity.corrected");
 reply.waitForFinished();
 if (reply.isError()){
     qDebug() << "error proxy \n";
   } 

Second function:
QDBusConnection connection = QDBusConnection::systemBus();

ch::epfl::mobots::AsebaNetwork network(DBUS_SERVICE_ASEBA, DBUS_PATH_ASEBA, connection);
QDBusPendingReply<Values> replyV = network.GetVariable("sensor-turret","sharp.value");
 replyV.waitForFinished();   
QDBusPendingReply<Values> replyA = network.GetVariable("sensor-turret","sharp.angle");
replyA.waitForFinished();
if (replyV.isError()||replyA.isError()){    
 qDebug() << "error sharp \n";
  } 

but some times I get this message:

QDBusConnectionPrivate::connectSignal: received error from D-Bus server while connecting signal to QDBusAbstractInterface::_q_serviceOwnerChanged(QString,QString,QString): org.freedesktop.DBus.Error.NoMemory (Not enough memory)
QDBusConnectionPrivate::connectSignal: received error from D-Bus server while connecting signal to QDBusAbstractInterface::_q_serviceOwnerChanged(QString,QString,QString): org.freedesktop.DBus.Error.NoMemory (Not enough memory)
error proxyQDBusConnectionPrivate::connectSignal: received error from D-Bus server while connecting signal to QDBusAbstractInterface::_q_serviceOwnerChanged(QString,QString,QString): org.freedesktop.DBus.Error.NoMemory (Not enough memory)
error sharpQDBusConnectionPrivate::connectSignal: received error from D-Bus server while connecting signal to QDBusAbstractInterface::_q_serviceOwnerChanged(QString,QString,QString): org.freedesktop.DBus.Error.NoMemory (Not enough memory)

When I run only one function in a time, I don't get this message and the execution go very well.

Is there any way to avoid this problem?

Best regards