Simulink Support Package for Arduino Installation Problem

I have been trying to install Simulink Support Package for Arduino in MATLAB 2012b and having some trouble. I am using Arduino Mega 2560 and Arduino IDE 1.0.3

-I downloaded arduino_r2012b_v2_0.zip(actually I also tried rtt_arduinomega2560_r2012a_v1_0.zip, but it didn't even saw that zip)
-typed 'targetinstaller' in matlab
-I chose 'folder' to select the support package
-I got the error message 'A dependent support package- Arduino Uno is missing. Please make sure the folder includes all the required files for Arduino support package.'

I can install 'Embedded Coder Support Package for Arduino' and use it perfectly, but it lacks 'External Mode'.
I am aware that choosing 'internet' instead of 'folder' would do the trick, but I must install the package to an 'offline PC'.

I also tried MATLAB Support Package for Arduino (aka ArduinoIO Package, which is said to support External Mode))
-I downloaded ArduinoIO.zip
-opened adiosrv.pde on ArduinoIDE and uploaded the sketch on arduino
-typed 'install_arduino' and Matlab saved the path
-I typed 'a=arduino('COM3') (COM3 is my port that is connected to arduino mega)
-I got the error message ' Error Using Arduino Too many input arguments'

Thank you for your attention

Sorry for late reply to your post am new here and i intend to help

first of all u need to install internet package for your Matlab and secondary
refers to this website for installation
http://www.sourcecodeonline.com/details/simulink_support_package_for_arduino_uno_hardware.html

hope this well be helpful

where did you get the .zip files from? I need the arduinobase file and can't find it. Installing through matlab is not working