Problem in SIM900 GPRS connection

I make simple code to read web page by ITEAD Gboard. Here is my code:

  Serial.write("\nStarting..........\n");
  mySerial.print("AT+CSQ");
  delay(1000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());

  Serial.write("\n-----1-----\n");

  mySerial.println("AT+CGATT=1");
  delay(1000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());

  Serial.write("\n-----2-----\n");

  mySerial.println("AT+CGATT?");
  delay(1000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());    

  Serial.write("\n-----3-----\n");

  mySerial.print("AT+SAPBR=3,1,\"CONTYPE\",\"GPRS\"");
  delay(1000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());

  Serial.write("\n-----4-----\n");

  mySerial.print("AT+SAPBR=3,1,\"APN\",\"internet\"");
  delay(2000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());

  Serial.write("\n-----5-----\n");

  mySerial.print("AT+SAPBR=1,1");
  delay(1000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());

  Serial.write("\n-----6-----\n");

  mySerial.print("AT+HTTPINIT");
  delay(1000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());

  Serial.write("\n-----7-----\n");

  mySerial.print("AT+HTTPPARA=\"URL\",\"xx.xx.xx.xx/my/web/site\"");
  delay(1000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());

  Serial.write("\n-----8-----\n");

  mySerial.print("AT+HTTPDATA=100,1000");
  delay(10000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());

  Serial.write("\n-----9-----\n");

  mySerial.println("AT+HTTPREAD");
  delay(1000);

  while(mySerial.available()!=0)
    Serial.write(mySerial.read());

  Serial.write("\nend.\n");

Which i get the following output:

Starting..........
AT+CSQ
-----1-----
AT+CGATT=1

ERROR

-----2-----
AT+CGATT?

+CGATT: 1

OK

-----3-----
AT+SAPBR=3,1,"CONTYPE","GPRS"
-----4-----
AT+SAPBR=3,1,"APN","internet"
-----5-----
AT+SAPBR=1,1
-----6-----
AT+HTTPINIT
-----7-----
AT+HTTPPARA="URL","xx.xx.xx.xx/my/web/site"
-----8-----
AT+HTTPDATA=100,1000
-----9-----
AT+HTTPREAD

ERROR

end.

AT+HTTPREAD return error. What wrong with me?

Note

xx.xx.xx.xx/my/web/site is my web page. The error is still there for all web page.