FC5 + Asterisk + Festival didn't work

I’d problem on run text to speech in Asterisk. It seems “(msgcall, 1, 1) exited non-zero” can’t communicate with festival server. However according to festival’s log, Asterisk had been connected.

Asterisk log :
– Executing Festival(“SIP/eddy-8980”, “Hello asterisk user how are you toda
y?”) in new stack
== Parsing ‘/etc/asterisk/festival.conf’: Found
== Spawn extension (msgcall, 1, 1) exited non-zero on 'SIP/eddy-8980’
May 17 15:48:11 NOTICE[31543]: pbx_spool.c:277 attempt_thread: Call completed to

in extensions.conf
exten => 956,1,Wait(1) ; Wait a second, just for fun
exten => 956,n,Answer ; Answer the line
exten => 956,n,Set(TIMEOUT(digit)=5) ; Set Digit Timeout to 5 seconds
exten => 956,n,Set(TIMEOUT(response)=10) ; Set Response Timeout to 10 seconds
exten => 956,n(restart),Background(conf-getpin)
exten => 956,n(instruct),BackGround(demo-instruct) ; Play some instructions
exten => 956,n,WaitExten ; Wait for an extension to be dialed.
exten => 1,1,Festival(‘Hello asterisk user how are you today?’)
exten => 1,n,Goto(956,restart) ; Start with the congratulations
exten => 2,1,BackGround(demo-moreinfo) ; Give some more information.
exten => 2,n,Goto(956,instruct)