Zaptel causes kernel: FIXME: per-channel check for O_NONBLOCK

[Michel Seliverstoff]

Hello, I just upgraded to 7.2-RELEASE-p2 with asterisk-1.4.25 and 
zaptel-1.4.11_1

Each time I receive a call on my zap 1 channel and route it to my zap 
channel 2 the call goes through but I get this message in my syslog:
Jul 29 22:09:15 freebsd kernel: FIXME: per-channel check for O_NONBLOCK

this coincides with these entries in /var/log/asterisk/debug:
[Jul 29 22:09:05] VERBOSE[20007] logger.c:     -- Executing 
[s at inbound:21] Dial("Zap/1-1", "Zap/g2|22") in new stack
[Jul 29 22:09:05] WARNING[20007] chan_dahdi.c: Unable to reset default 
ring on 'Zap/2-1': Bad address
[Jul 29 22:09:05] VERBOSE[20007] logger.c:     -- Called g2
[Jul 29 22:09:05] VERBOSE[20007] logger.c:     -- Zap/2-1 is ringing
[Jul 29 22:09:07] VERBOSE[20007] logger.c:     -- Zap/2-1 is ringing
[Jul 29 22:09:13] VERBOSE[20007] logger.c:     -- Zap/2-1 is ringing
[Jul 29 22:09:14] VERBOSE[20007] logger.c:     -- Hungup 'Zap/2-1'
[Jul 29 22:09:14] VERBOSE[20007] logger.c:   == Spawn extension 
(inbound, s, 21) exited non-zero on 'Zap/1-1'
[Jul 29 22:09:14] VERBOSE[20007] logger.c:     -- Executing 
[h at inbound:1] DeadAGI("Zap/1-1", "script.sh") in new stack
[Jul 29 22:09:14] VERBOSE[20007] logger.c:     -- Launched AGI Script 
/usr/local/share/asterisk/agi-bin/script.sh
[Jul 29 22:09:16] VERBOSE[20007] logger.c:     -- AGI Script vmail.sh 
completed, returning 0

my extensions.conf
exten => s,n,Dial(Zap/g2,22) ...and later
exten => h,1,DeadAGI(script.sh)

If I replace the Zap/g2 with a SIP channel then I don't get the message. 
Is there something I can do about this?

Thanks for your help,
Michel