I was getting similar problems and also created a post. Assuming you have the SIM in the right way and you are in an area that has 2G coverage, I am really not sure what the problem is. I got it working once or twice but going back to it, it would stop working. The best results I got was to use a terminal program and enter the AT commands by hand!
I have since moved on and use the NOVA with its 4G coverage and have much more success with the tutorials.