AppleScript to arduino

So I have a small project that I am working on and I need some basic commands to arduino. Each command is one character long. For the test I have application that turns on a LED if a "l" character is recieved. So I tryed that with the serial monitor - it wroks.

But now I want to turn that LED on with appleScript. I found a serialPort X (applescript extension that should enable serial communication). So I can open the port to the arduino. But I can't figure out how to turn the LED on with it. If I do this serialport write "l" to portRef
that should send an l character to the arduino and turn on the LED - but it doesn't. I see the serial RX/TX LEDs blink on the arduino and the LED blinks too - but it doesn't stay on (it should stay on). So why isn't this working?

EDIT: The above script works if arduino IDE is in "Serial Monitor" mode. But if the arduino software isn't working the thing wont work.

EDIT2: I also tryed this code:
http://todbot.com/blog/2006/12/06/arduino-serial-c-code-to-talk-to-arduino/
And the results are the same. The thing works if the arduino IDE is in "Serial Monitoring" but if it isn't I just get a LED that blinks when I press enter.

What happens if you try to send from apple script serveral times fast one after the other ? Do you see one blink or serveral ?

Maybee something happens that resets the Arduino board right after it turns the LED on.

Just one blink! I thought about the board resetting after it gets the message too. Because if I unplug the board and then plug it in I get the same result. RX blinks, TX blinks and LED blinks. One after the other.

I know nothing about Mac's and applescript, but it might have something to do with how apple script handles the DTR signal in the serial port connection.

EDIT:

Try to read this thread:

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1204641836

Well since I tryed it with normal C that works on linux/windows/mac and I got the same results the problem probably isn't with applescript. But somewhere else.

I also tryed the same code with another arduino (Duemilanove too but with Atmega 328). And the results are almost identical. About disabling the auto reset - i don't know if this is the problem.

EDIT: Disabled the autoreset by wiring 100ohm resistor between +5V and reset. And now the whole thing is working. But as I read this should only be used as a temp solution. I need something thal last a little longer.