GSM + EasyVR shields Problem

[Reem]

Hello everyone..

I have an arduino uno and GSM/GPRS/GPS shield I got from dfrobot http://www.dfrobot.com/index.php?route=product/product&product_id=673#.Uf1Mam1vC1s and it is working fine .. and I also have an easyvr shield and also working fine .. but when I stack them all together only one of them works.. There is no conflict in pins but it is not working.. any idea what is the problem :~??