sms/gps tracking system

hello am doing a project SMS/GPS Vehicle tracking

system, i am using a philips 8051 microcontroller (XA-

G49), to be programned in c language, a garmin 18X-LVC

gprs receiver, and a Cinterion MC55i Terminal Quad Band

(GSM Module)
I have connected the micro controller to the gsm module

via rs232 male-male cable, and also took the white wire

from the gprs receiver which i connected to pin 1.4 on

the micro controller. i keep sending the request from

the main operator my phone and have done every thing i

think is right with the code, but still get no

response.
Please could any one give a hint on how to go about

this whole issue perhaps i may be doing some thing

wrong with the connection or the choice of my

apparatus may be wrong.
Please any possible hint would help a lot