CC2530: problem with low power mode

Hi,

i work on a zigbee remote with a CC2530 item.

The communication between 2 modules work fine but I would like that my remote enter in a low power mode when no button is pressed.

I have write this command in my code:

SLEEPCMD = SLEEPCMD | 0x03;
PCON = 0x01;

in debug mode the programm stop after the PCON command and whe i pressed a button the program run.

But i have sometimes a few troubleshooting, Sometimes the program counter is lost or when it is not lost, I am not able to send correctly a message to the other device.

Have you got an idee for this problem?

Regards