i have a problem with simulated PTZ camera. I'm using a canon VCC4 and i'd like that this camera can center a green blob: so if blob is on left of FOV, camera rotate in counterclockwise and viceversa if blob is on right of FOV.
This is my simple code:

for (i=0 ; i< blobfinder->blobs_count; i++)
      green = (blobfinder->blobs[i].color&color) >> 8;
      if (green != 0)
         if (blobfinder->blobs[i].x < 160 )
           playerc_ptz_set(ptz, ptz->pan+0.1 , 0 ,ptz->zoom );
          playerc_ptz_set(ptz,ptz->pan-0.1, 0, ptz->zoom);

But i get this warning message when playerc_ptz_set is execute :
"warning : Unhandled message for driver device=16777343:7000:8:0 type=2 subtype=1 len=20" 
 Why ???
Nevertheless the camera  can  move  but  this message  appear  repeatedly  for  each of my four robots and i think these messages  slow down simulation.
I'm running Gazebo 0.6.0 and player 2.0.2

thanks in advance