No Zap channel available for conference

hi, im using web-meetme to control my conference bridge, all is working fine but the user announce, i got this error :

[Nov 18 10:53:36] NOTICE[29851]: app_cbmysql.c:534 cb_exec: checkMax: 1
[Nov 18 10:53:36] NOTICE[29851]: app_cbmysql.c:362 enterConf: Roomtype: 86277|di|
[Nov 18 10:53:36] WARNING[29851]: app_meetme.c:2469 find_conf: No Zap channel available for conference, user introduction disabled

I dont have any zaptel hardware, im using ztdummy for time source device.
the asterisk version is 1.4, i have another * server running 1.2 without zaptel hardware and the announce is working fine,
what should i check?