ooh323 can not pickup the calls

i used Asterisk 1.4.7.1 and Asterisk-add 1.4.2. Ooh323 have been compiled successfully.

*CLI> show channeltypes can get Ooh323 information.

call from H323 can access Asterisk Server.but call was hung up quickly,can hear nothing,even i just make a playback a Audio file.
For example:
IN extension.conf
exten => 6666,1,Playback(greeting2newsys)
exten => 6666,2,Hangup

i dialed 6666 to the Asterisk server.
ooh323 debug information as following .Thanks for any ideas.thanks again.

— onNewCallCreated ooh323c_3
+++ onNewCallCreated ooh323c_3
— ooh323_onReceivedSetup ooh323c_3
— find_user
+++ find_user
Adding capabilities to call(incoming, ooh323c_3)
— configure_local_rtp
+++ configure_local_rtp
+++ ooh323_onReceivedSetup - Determined context default, extension 6666
— onAlerting ooh323c_3
— find_call
+++ find_call
+++ onAlerting ooh323c_3
– Executing [6666@default:1] Playback(“OOH323/szhyy001-c43a”, “greeting2newsys”) in new stack
— ooh323_answer
— onCallEstablished ooh323c_3
— find_call
+++ find_call
+++ ooh323_answer
– <OOH323/szhyy001-c43a> Playing ‘greeting2newsys’ (language ‘en’)
+++ onCallEstablished ooh323c_3
— onCallCleared ooh323c_3
— find_call
+++ find_call
== Spawn extension (default, 6666, 1) exited non-zero on ‘OOH323/szhyy001-c43a’
— ooh323_hangup
hanging szhyy001
+++ ooh323_hangup
— ooh323_destroy
Destroying szhyy001
+++ ooh323_destroy
*CLI>