Arduino Plugin Error = Exception in UDPGetMessage

HI,

Since some time now I get the error message in the log:

'Arduino Plugin Error = Exception in UDPGetMessage : Operation on non-blocking socket would block'

Can anyone give me a clue where to look for the solution of this problem. Is it something in the sketch? I am reading the data from a Cozir CO2 sensor and sending that to HS.
My whole code looks like:

void setup() {
HSSetup();
Serial.begin(9600);
//Startup Cozir Sensor
czr.SetOperatingMode(CZR_POLLING);
czr.SetDigiFilter(64);
}

void loop() {
#if ISIP == 1
IsUDP();
#endif
// wait interval1
unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= interval1) {
previousMillis = currentMillis;
//read sensor
cotwo = czr.CO2();
t = czr.Celsius();
h = czr.Humidity();

SendToHS(1, cotwo);
SendToHS(2, t);
SendToHS(3, h);
}

/*Execute regardless of connection status*/

if (IsConnected == true) {
/*Execute ONLY when HomeSeer is connected*/

}
}

About the parameters: t and h are float and cotwo is int.

thanks in advance!
Cor