How Can I Connect two B400P cards in two asterisks?

hi, all of users:
my scenario is that Asterisk A is set with B400P in TE,TE,TE,TE Model and Asterisk B is set with B400P in TE,TE,NT,NT. Now I want to use NT(ISDN phone) call second NT port and the second NT port in Asterisk B forward to Asterisk A TE port. the physical connection is that second NT port is connecting with Asterisk A TE port. it shows like this:

NT(ISDNphone) in Asterisk B-----> call second NT in asterisk B------>forward to TE port in Asterisk A----->play IVR in Asterisk A.

the physical connection seems OK. the LEDs are in green if NT in asterisk B port connecting TE port in Asterisk A.

Asterisk B:

zapata.conf
[channels]

switchtype = euroisdn

pridialplan = dynamic
prilocaldialplan = local
nationalprefix = 0
internationalprefix = 00
usecallingpres=yes

echocancel = yes
echocancelwhenbridged = yes
echotraining = 100

overlapdial=yes
;-------------------------------------------------------------------
; p2p TE mode (for connecting ISDN lines in point-to-point mode)
signalling = bri_cpe
context=from-isdn

group = 1

; S/T port 1-2 (first quadBRI, or lower ports of an octoBRI)
;channel => 1-2
;channel => 4-5

;-------------------------------------------------------------------

; p2p NT mode (for connecting an ISDN PBX in point-to-point mode)
context=from-internal
group = 2
signalling = bri_net_ptmp
overlapdial=yes
; S/T port 3-4 (second quadBRI, or upper ports of an octoBRI)
channel => 7-8
channel => 10-11
extensions.conf:
; incoming ISDN BRI calls arrive in this context
; and are routed to zaptel group 2 (NT ports to the pbx)

[from-isdn]
exten => s,1,Wait(1)
exten => s,2,Playback(demo-echotest);
exten => s,3,Hangup

[from-internal]
exten => 100,1,Dial(zap/7&zap/8) ; connecting wit TE port in Asterisk A
exten => 100,2,Hangup

Asterisk A:
[channels]

switchtype = euroisdn
pridialplan = dynamic
prilocaldialplan = local
nationalprefix = 0
internationalprefix = 00
usecallingpres=yes
echocancel = yes
echocancelwhenbridged = yes
echotraining = 100

overlapdial=yes
;-------------------------------------------------------------------
; p2p TE mode (for connecting ISDN lines in point-to-point mode)
;context=from-internal
context=ml
signalling = bri_cpe
group = 1

; S/T port 1-4 (first quadBRI, or lower ports of an octoBRI)
channel => 1-2
channel => 4-5
channel => 7-8
channel => 10-11
;-------------------------------

extensions.conf:
; incoming ISDN BRI calls arrive in this context
; and are routed to zaptel group 2 (NT ports to the pbx)

[ml]
exten => 8,1,Wait(5)
exten => 8,2,Playback(demo-echotest)
exten => 8,3,Hangup()

exten => 7,1,Wait(5)
exten => 7,2,Playback(demo-echotest)
exten => 7,3,Hangup()

when i dial 100, will call NT port 3 which has two channels 7 and 8.
the errors are shown :

In asterisk B:
Verbosity is at least 30
– Remote UNIX connection
== Primary D-Channel on span 4 up for TEI 64
– Accepting overlap voice call from ‘’ to ‘’ on channel 0/2, span 4
– Starting simple switch on ‘Zap/11-1’
– Executing Dial(“Zap/11-1”, “zap/7&zap/8”) in new stack
– Requested transfer capability: 0x00 - SPEECH
– Called 7
– Requested transfer capability: 0x00 - SPEECH
– Called 8
– Channel 0/2, span 4 got hangup request, cause 16
– Hungup ‘Zap/8-1’
– Hungup ‘Zap/7-1’
== Spawn extension (from-internal, 100, 1) exited non-zero on ‘Zap/11-1’
– Hungup ‘Zap/11-1’

in asterisk A:
t 20 22:13:20 WARNING[2720]: chan_zap.c:2683 pri_find_dchan: No D-channels available! Using Primary channel 9 as D-channel anyway!
== Primary D-Channel on span 4 down
Oct 20 22:13:20 WARNING[2721]: chan_zap.c:2683 pri_find_dchan: No D-channels available! Using Primary channel 12 as D-channel anyway!
– Accepting voice call from ‘’ to ‘7’ on channel 0/1, span 1
– Executing Wait(“Zap/1-1”, “5”) in new stack
– Accepting voice call from ‘’ to ‘8’ on channel 0/2, span 1
– Executing Wait(“Zap/2-1”, “5”) in new stack

I guess something wrong in zapata.conf or physical connection and all channels are in both of asterisk A and B are down.
please give me a hint for such case.
thanks!
zhu8080