This is my first time using the Arduino so I apologize if this is a simple question. I am trying to download a simple program to my Arduino that blinks an led on and off however, I think I am having some trouble with my serial port connection because every time I press the button that downloads the code i get a null pointer exception and I get the same error whey I try and open simple serial port communication. I appreciate any help you guys can give me thank you for your time.
You have to pick the right serial port from the Tools > Serial Port menu. On the Mac, this is something like /dev/tty.usbserial...., on Windows it should be the COM port that corresponds to the USB-serial device in your Device Manager. In both cases, you need to have installed the drivers first. Also, on Windows the port number has to be less than 10.
Arduino 0010 will have a better error message for this (I just changed it), and should support com ports over 10.