Simulink external mode doesn't recognize /dev/ttyUSB1 serial port

Hi, this is a very weird error, seems that on Linux Simulink isn't capable of recognizing the serial port

I'm generating a new target (for the Zybo board). This is what I do to add the serial interface:

io = addNewSerialInterface(hw,'My Serial Interface');

io.DefaultPort = '/dev/ttyUSB1';

io.AvailablePorts = {'/dev/ttyUSB1', '/dev/ttyUSB0', '/ttyUSB1', 'ttyUSB1', '\dev\ttyUSB1', '\ttyUSB1', '\/dev\/ttyUSB1', '\/ttyUSB1', '\\dev\\ttyUSB1'};

io

ext = addNewExternalMode(tgt,'New External mode');

It seems that it doesn't matter what i put there Simulink doens't recognize the serial port, every time I start the external mode it gives me this error:

Error occurred while parsing External Mode MEX-file arguments '1 /dev/ttyUSB1 115200 30'.

Caused by:

Unrecognized function or variable 'dev'.

Does anyone have a solution to this problem?