Arduino uno and Seeed studio GPRS shield

HI
Please help me!!!
I m using Arduino uno and Seeed studio GPRS shield, but I am getting out put:

GSM Shield testing.
DB:NO RESP
DB:NO RESP
DB:NO RESP
ERROR: SIM900 doesn’t answer. Check power and serial pins in GSM.cpp
status=IDLE

I attached with power, jumpers D7(RX) and D8(TX) in Seeed studio GPRS shield

I used:

#include <SoftwareSerial.h>
#define GSM_TXPIN 7
#define GSM_RXPIN 8

#include “SIM900.h”

//If not used, is better to exclude the HTTP library,
//for RAM saving.
//If your sketch reboots itself proprably you have finished,
//your memory available.
//#include “inetGSM.h”

//If you want to use the Arduino functions to manage SMS, uncomment the lines below.
#include “sms.h”
SMSGSM sms;

//To change pins for Software Serial, use the two lines in GSM.cpp.

//GSM Shield for Arduino
//www.open-electronics.org
//this code is based on the example of Arduino Labs.

//Simple sketch to send and receive SMS.

int numdata;
boolean started=false;
char smsbuffer[160];
char n[20];

void setup()
{
//Serial connection.
Serial.begin(9600);
Serial.println(“GSM Shield testing.”);
//Start configuration of shield with baudrate.
//For http uses is raccomanded to use 4800 2400or slower.
if (gsm.begin(9600)){
Serial.println("\nstatus=READY");
started=true;
}
else Serial.println("\nstatus=IDLE");

if(started){
//Enable this two lines if you want to send an SMS.
if (sms.SendSMS("+971505393365", “Arduino SMS”))
Serial.println("\nSMS sent OK");
}

};

void loop()
{
if(started){
//Read if there are messages on SIM card and print them.
if(gsm.readSMS(smsbuffer, 160, n, 20))
{
Serial.println(n);
Serial.println(smsbuffer);
}
delay(1000);
}
};

What mistake i did?
Please anyone reply me, tks…

What is the library you are using , And how do you use this GPRS shield?
Can you provide more details.

Deray