problem with the midi bus library and multiple devices

hi , i use processing 2.2.1 the midibus library and live ableton as a midi output (using loopmidi for the virtual midi connecting)

i want to trigger different image in processing with different instrument of ableton using different midi devices.

my code works for a whyle: (3sec to 3min) and then gives me that error message:

The MidiBus Warning: Disabling noteOff(int channel, int pitch, int velocity) because an unkown exception was thrown and caught java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at themidibus.MidiBus.notifyParent(Unknown Source) at themidibus.MidiBus$MReceiver.send(Unknown Source) at com.sun.media.sound.AbstractMidiDevice$TransmitterList.sendMessage(Unknown Source) at com.sun.media.sound.MidiInDevice.callbackShortMessage(Unknown Source) at com.sun.media.sound.MidiInDevice.nGetMessages(Native Method) at com.sun.media.sound.MidiInDevice.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.RuntimeException: missing a pushMatrix() to go with that popMatrix() at processing.core.PGraphicsJava2D.popMatrix(PGraphicsJava2D.java:1812) at processing.core.PGraphicsJava2D.backgroundImpl(PGraphicsJava2D.java:2280) at processing.core.PGraphics.backgroundFromCalc(PGraphics.java:6983) at processing.core.PGraphics.background(PGraphics.java:6898) at processing.core.PApplet.background(PApplet.java:15122) at sketch_160111a.noteOff(sketch_160111a.java:52) ... 10 more

there is my code:

                import themidibus.*;
                MidiBus myBus;


                void setup() {
                  background(0);
                  size(500, 500);

                  MidiBus.list();
                  myBus = new MidiBus(this, "loopMIDI Port",-1 );

                 myBus.addInput("loopMIDI Port 1");

                }
                void draw() {

                  int channel;
                  int pitch ;
                  int velocity ;

                }
                void noteOn(int channel, int pitch, int velocity ) {


                  if (channel == 1) {  // kik
                    background(100, 250, 0);
                  }
                  if (channel == 2 ) {            // rim
                    ellipse(50, 50, 80, 80);
                  }
                }

                void noteOff(int channel, int pitch, int velocity) {
                  background(0);
                }

                void delay(int time) {
                  int current = millis();
                  while (millis () < current+time) Thread.yield();
                }

the same code works fine if i stay one the same device input but i need to have mutiple input devices to trigger diferrent image at the same time in processing.

i tried different things but i don't understand what's wrong and have always the same message error ..

hope someone can help me..