asterisk users - Apr 2005 - Asterisk 1.0.5-BRIstuffed-0.2.0-RC7e

Hello ,
I'm making a setup with 2 QuadBRI and 2 S400P .

When i hangup some times i got a message :
8 18:25:05 WARNING[7356]: chan_zap.c:1470 zt_set_hook: zt hook failed:
Device or resource busy
but every things works fine .

Thanks .

Jalal .