Problem with IComSat v1.1 and HTTP POST

[codac]

Helly everybody,

I'm quite new to this topic.
Anyhow, since days and days I'm trying to get this running.

I'm using an Arduino Uno R3 with an IComSat v1.1 GSM/GPRS Shield from IteadStudio using the SIM900 module.
The IComSat v1.1 has set UART and PIN TXD: 2 and PIN TXD: 3.
According to this website: It says, the POWER_ON Pin is D9 and the RESET is D10.

In order to power this up, I have attached the Arduino to a 9V Battery as well as to the USB cable.

For the communication, I'm using a German T-Mobile SIM-Card with the following settings:
APN: internet.t-mobile
User: t-mobile
Pass: tm
PIN: disabled

I've tried a second SIM-Card of the company Fyve (Vodafone) with the following settings:
APN: web.vodafone.de
User:
Pass
PIN: disabled

I try to establish a GPRS connection to my website in order to store GPS information on 9600 baud. I've used the following AT command series:

    gprsSerial.println("AT+COPS=0");
    delay(2000);
    toSerial();
    gprsSerial.println("AT+CREG?");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+CIPSHUT");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+CGATT=1");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+SAPBR=3,1,\"CONTYPE\",\"GPRS\"");
    delay(2000); 
    toSerial();
    //T-Mobile
    //gprsSerial.println("AT+SAPBR=3,1,\"APN\",\"internet.t-mobile\"");
    //Fyve
    gprsSerial.println("AT+SAPBR=3,1,\"APN\",\"web.vodafone.de\"");
    delay(2000); 
    toSerial();
    //T-Mobile
    //gprsSerial.println("AT+SAPBR=3,1,\"USER\",\"t-mobile\"");
    //Fyve
    gprsSerial.println("AT+SAPBR=3,1,\"USER\",\"\"");
    delay(2000); 
    toSerial();
    //T-Mobile
    //gprsSerial.println("AT+SAPBR=3,1,\"PWD\",\"tm\"");
    //Fyve
    gprsSerial.println("AT+SAPBR=3,1,\"PWD\",\"\"");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+SAPBR=1,1");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+HTTPINIT");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+HTTPPARA=\"CID\",1");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+HTTPPARA=\"URL\",\"www.xxxxxxxxxxxx.de/app/location.php?time=123456\"");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+HTTPACTION=1");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+HTTPREAD=200");
    delay(2000); 
    toSerial();
    gprsSerial.println("AT+HTTPTERM");
    delay(2000); 
    toSerial();

This is the result with T-Mobile APN and SIM-Card enabled:

GSM Shield testing.
AT+COPS=0

OK

Call Ready
AT+CREG?

+CREG: 0,1

OK
AT+CIPSHUT

SHUT OK
AT+CGATT=1

OK
AT+SAPBR=3,1,"CONTYPE","GPRS"

OK
AT+SAPBR=3,1,"APN","internet.t-mobile"

OK
AT+SAPBR=3,1,"USER","t-mobile"

OK
AT+SAPBR=3,1,"PWD","tm"

OK
AT+SAPBR=1,1

OK
AT+HTTPPARA="CID",1

ERROR
AT+HTTPPARA="URL","www.xxxxxxxxxxxx.de/app/location.php?time=123456"AT+HTTPACTION=1

ERROR
AT+HTTPREAD=200

ERROR
AT+HTTPTERM

ERROR

And this is the result with Fyve APN and Sim-Card enabled:

GSM Shield testing.
AT+COPS=0

ERROR
AT+CREG?

+CREG: 0,3

OK
AT+CIPSHUT

ERROR
AT+CGATT=1

ERROR
AT+SAPBR=3,1,"CONTYPE","GPRS"

ERROR
AT+SAPBR=3,1,"APN","web.vodafone.de"

ERROR
AT+SAPBR=3,1,"USER",""

ERROR
AT+SAPBR=3,1,"PWD",""

ERROR
AT+SAPBR=1,1

ERROR
AT+HTTPINIT

ERROR
AT+HTTPPARA="CID",1

ERROR
AT+HTTPPARA="URL","www.xxxxxxxxxxxx.de/app/location.php?time=123456"AT+HTTPACTION=1

ERROR
AT+HTTPREAD=200

ERROR
AT+HTTPTERM

ERROR

Any idea what the problem might be?
Any help is greatly appreciated!