Wifi Shielf Firmware Upgrade

I recently purchased the official arduino wifi shield from sparkfun. I am trying to follow a tutorial on Xively.com that would establish bidirectional communication between my arduino and the Xively dashboard. I have successfully gotten my the wifi shield and Arduino communicating on my wireless network, but I am unable to get it to communicate with Xively. There is an HTTP error. After some research and running some example sketches, it appears that I need to upgrade the firmware. I have tried following the procedure on the Arduino website:
http://arduino.cc/en/Hacking/WiFiShieldFirmwareUpgrading#.UySw_fldW6w
but it is lacking in several areas and I am at my wits end trying to figure it out.
I am not sure what Github files to grab and where to put them on my computer.
I attached some pictures of the procedure I was following.

Eventually when I am using the command prompt (after I downloaded Flip), I get an error when the program tries "opening port". This error is attached below. Do I need drivers to communicate with the standalone shield?

It seems like upgrading the firmware should not be that difficult but there are not current thorough tutorial that I have found.

Any help would be much appreciated...
Thanks

arduinoQuestions.pdf (278 KB)

This is another step by step guidance, might help

Great! I got it and I used a the link you posted to grab the drivers so it would be recognized as a usb driver.
I ended up just continuing with the tutorial on the arduino website and it worked. I now have bidirectional communication with xively!