NxView does not work very well with external triggers. It triggers frequently and clears the image buffers when doing so. If that happens right when some of the cameras have already received images and others have not, then the already received images get discarded. The next Receive command will then find some images missing and return unsuccessfully. I found multiple instances of this in your log file:
When using an external trigger, it is important to coordinate the NxLib commands with the trigger sequence: when to Trigger, how long to wait for in Retrieve. NxView, having no knowledge about your trigger sequence, cannot reliably do this.
Because NxView does not explicitly set a Timeout on the Retrieve command, the computed value of 484 is used. This also means that you can overwrite this using the DefaultParameters node, i.e. by setting DefaultParameters/Retrive/Timeout to some larger value in NxTreeEdit. That should help.
