chan_zap.c:8203 pri_dchannel Error

I am receiving the follow error

chan_zap.c:8203 pri_dchannel: PRI got event: HDLC Abort (6) on Primary D-channel of span 5

I am getting one message like this every 2-3 seconds. I am also only getting this error from one of the 8 spans I have configured.

The switch on the other side has all spans configured exactly the same.

My configuration information is as follows:

Asterisk 1.2.4
Zaptel 1.2.4

zaptel.conf

Zaptel Configuration File

loadzone=us
defaultzone=us

span=1,1,0,esf,b8zs # Card 1, Port 1: NACT Switch
bchan=1-23 # STX Port 17/3
dchan=24

span=2,2,0,esf,b8zs # Card 1, Port 2: NACT Switch
bchan=25-47 # STX Port 12/7
dchan=48

span=3,3,0,esf,b8zs # Card 1, Port 3: NACT Switch
bchan=49-71 # STX Port 12/3
dchan=72

span=4,4,0,esf,b8zs # Card 1, Port 4: NACT Switch
bchan=73-95 # STX Port 13/3
dchan=96

span=5,1,0,esf,b8zs # Card 2, Port 1: NACT Switch
bchan=97-119 # STX Port 14/7
dchan=120

span=6,2,0,esf,b8zs # Card 2, Port 2: NACT Switch
bchan=121-143 # STX Port 16/5
dchan=144

span=7,3,0,esf,b8zs # Card 2, Port 3: NACT Switch
bchan=145-167 # STX Port 17/5
dchan=168

span=8,4,0,esf,b8zs # Card 2, Port 4: NACT Switch
bchan=169-191 # STX Port 17/6
dchan=192

zapata.conf

[channels]
context=default
usecallerid=yes
hidecallerid=no
callwaiting=yes
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
cancallforward=yes
callreturn=yes
echocancel=128
echocancelwhenbridged=yes
echotraining=600
rxgain=0.0
txgain=0.0
immediate=no

signalling=pri_cpe
pridialplan=unknown
prilocaldialplan=international

group=1
context=iti-service
switchtype=national
channel=>1-23

group=2
context=networkip
switchtype=national
channel=>25-47

group=3
context=att_sip
switchtype=national
channel=>49-71,145-167