Problem with GPRS shield (no communication at all)

I have an iComSat v1.0 Arduino shield from iteadstudio and I still can’t get it working properly.

SIM900 GSM/GPRS shield for Arduino - IComSat v1.0
IComsat is a GSM/GPRS shield for Arduino and based on the SIM900 Quad-band GSM/GPRS module. It is controlled via AT commands (GSM 07.07)

I bought the shield from:

iteadstudio.com/store/index.php? … cts_id=413

These are the problems that myself and many other people are experiencing:

arduino.cc/forum/index.php/topic … #msg609237

I keep getting a problem:

system startup
no response

SMS ERROR
etc, etc