LCP: timeout sending Config-Requests

Hi I am trying to integrate the GR64 on a PDA but I am having troubles.

The error I got is the following:[i]
Serial connection established.
Using interface ppp0
Connect: ppp0 <–> /dev/ttyS1
LCP: timeout sending Config-Requests
Connection terminated.

Sending break to the modem

PDP context detached
Serial link disconnected.

[1]+ Exit 10 pppd call gprs[/i]

I would appreciate any help on this topic, I am new at this stuff and I have no idea where my problem is.
Thanks.