Phpagi get_data

I’ve a problem with the get_data funcion of the phpagi.php library.
Have a Sip trunk and a DID that call my php script:

exten => AGI(myscript.php)

In this script i use get_data function.
With one call is all ok, but if i have two calls simultaneously the function get_data return a timeout even if a semd dtmf tones.

Can you help me.
Thanks.

You can start debugging agi(If you have not already done it)
by typing ‘agi debug’ on the asterisk CLI.

You can then see the messages for AGI when the script is run.
If you require any help then post the messages seen on the CLI
when the AGI script is run.

Thank you!

With Agi debug i see nothing else that result of get_data function is : result= (timeout).
I have this problem when i have two calls on the same trunk.
Can asterisk run the same agi script (php) for two calls coming from the same SIP account?

thanks