The d-channel is going up and down

Hi. I'm using trixbox with a fonebridge with 2 spans. I'm just using one for now,for testing.

I'm doing some tests with my fonebridge using a half PRI connection with 16 channels.
When i'm trying to call out via trunk zaptel sometimes i got all channels busy.

When i see the log i get:

-- Playing 'all-circuits-busy-now'
== Primary D-Channel on span 1 up
== Primary D-Channel on span 1 down
== Primary D-Channel on span 1 up

and all the calls being made just go off.

Anyone had this problem?

here's my conf files:

[trixbox1 ~]# cat /etc/redfone.conf
[globals]
# IP-address of the IP Configuration port
# Factory defaults are; FB1=192.168.1.254 FB2=192.168.1.253
fb=192.168.1.254
# Which port to use for TDMoE Traffic (1 or 2)
port=1
# Which Asterisk server destination MAC address for TDMoE Traffic?
server=00:19:B9:EE:BE:63

# E1 PRI SPAN WITH CRC4, SLAVE TO TELCO
[span1]
framing=ccs
encoding=hdb3
slave

[span2]
framing=ccs
encoding=hdb3
master

[trixbox1 ~]# cat /etc/zaptel.conf
# Autogenerated by /usr/sbin/genzaptelconf -- do not hand edit
# Zaptel Configuration File
#
# This file is parsed by the Zaptel Configurator, ztcfg
#

# It must be in the module loading order

dynamic=ethmf,eth1/00:50:C2:65:D2:18/0,31,0
dynamic=ethmf,eth1/00:50:C2:65:D2:18/1,31,1
#
bchan=1-15,17-31
dchan=16
bchan=32-46,48-62
dchan=47
#
# NOTE: Most E1 use alaw codec and this must be specified.
alaw=1-62
#alaw=1-31
#
loadzone = pt
defaultzone=pt

[trixbox1 ~]# cat /etc/asterisk/zapata.conf
;
; Zapata telephony interface
;
; Configuration file

[trunkgroups]

[channels]
language = pt
switchtype = euroisdn
signalling = pri_cpe
context=from-zaptel
group = 0
channel => 1-15

;Include AMP configs
#include zapata_additional.conf