Reset arduino with GPRSBee


I am working with the gprsbee with my arduino board. I would like to reset the arduino board with the RI pin of gprsbee but I have a problem.
To connect the RI to the arduino I am using a capacitor and resistor in serie. My problem is this:

I put the gprsbee in sleep mode(AT+CSCLK=1) and I wait some time in the loop. Then the arduino sends data via gprs, but some times, this reset the Arduino.
This happens when using the DTR signal (pull down dtr pin) to wake up the radio.

Any solution tu reset the arduino board with RI pin?