problem with enabling graphics in matlab

Hi,

I am trying to activate plot option from matlab but something is not working right. Here are the steps that I follow:
- In a terminal window I run "comsolserver -graphics"
- Open matlab and type in
>> addpath 'C:\Program Files\COMSOL\COMSOL43b\mli'
>> import com.comsol.model.*
>>import com.comsol.model.util.*
- Run an m-file that I saved from Comsol GUI
- then try to run
model.study('std1').feature('eig').set('plot','on')
but I get this error message

Java exception occurred:
Exception:
com.comsol.util.exceptions.UnknownEntityException: Unknown property
Messages:
Unknown property
- Property: plot

I appreciate your help.
Thanks,
Amir