GPRS shield unable to send text

I bought a GPRS shield years ago. I’m using it for the first time now and I can’t get it to send text.

I downloaded a library for the GPRS shield, this was one of the send SMS example sketches:

/*
GPRS Connect TCP

This sketch is used to test seeeduino GPRS_Shield's send SMS func.
to make it work, you should insert SIM card to Seeeduino GPRS 
and replace the phoneNumber,enjoy it!

create on 2015/05/14, version: 1.0
by lawliet.zou(lawliet.zou@gmail.com)
*/
#include <GPRS_Shield_Arduino.h>
#include <SoftwareSerial.h>
#include <Wire.h>

#define PIN_TX    7
#define PIN_RX    8
#define BAUDRATE  9600
#define PHONE_NUMBER "country code + my phone number"
#define MESSAGE  "hello,world"

GPRS gprsTest(PIN_TX,PIN_RX,BAUDRATE);//RX,TX,BaudRate

void setup() {
  Serial.begin(9600);
  while(!gprsTest.init()) {
      delay(1000);
      Serial.print("init error\r\n");
  }  
  Serial.println("gprs init success");
  Serial.println("start to send message ...");
  gprsTest.sendSMS(PHONE_NUMBER,MESSAGE); //define phone number and text
}

void loop() {
  //nothing to do
}

I go to monitor, and it keeps printing “init error” , any ideas…?

I bought a GPRS shield years ago

Which one?

I downloaded a library for the GPRS shield

For A GPRS shield? Or, for YOUR GPRS shield? The libraries are not interchangeable.

Your thread title presumes that you are able to connect to the shield, but are not able to then send messages. That is obviously not the case.