DDNS and PTR records bind-9.1.2: a problem?

[Alvise Nobile]

Bind 9.1.2: I try to update a PTR record using nsupdate, and the
transaction aborts in a way that looks odd:

nsupdate -k keyfile -d <<--EOF-- 
prereq nxrrset 99.27.21.10.in-addr.arpa.  PTR X.nl2.ictp.trieste.it.
update add 99.27.21.10.in-addr.arpa.    5000 PTR XXX.nl2.ictp.trieste.it.    

--EOF-- 

Output:

keycreate 
Reply from SOA query: ;; ->>HEADER<<- opcode: QUERY, status:
NXDOMAIN, id:  41560 ;; flags: qr aa rd ra ; QUESTION: 1, ANSWER: 0,
AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;
98.27.21.10.in-addr.arpa.  IN SOA
 
;; AUTHORITY SECTION: 10.in-addr.arpa.  0 IN SOA
server.nl2.ictp.trieste.it. root.server.nl2.ictp.trieste.it. 2001033397 28800 7200 604800 86400
 
 
Found zone name: 10.in-addr.arpa 
The master is: server.nl2.ictp.trieste.it
rdata/generic/ptr_12.c:87: REQUIRE(rdata->length != 0) failed.
Aborted                             


-------------------

The PTR record I'm testing does not exist in the zone. 
Trying the 'update add' alone (without prereq testing) does not act at
all:
nsupdate -k /etc/keys/KDHCPD_UPDATES.+157+03800.private -d /tmp/A33
keycreate 
Freeing key 
Destroy DST lib
Detach from entropy      

Analogous updates to the A records in the direct zone succeed. The two
zones (10.in-addr.arpa. and nl2.ictp.trieste.it.) are described in the
essentially the same way in named.conf. 

Could someone tell me if I'm doing something wrong, or there is a real
problem?

PS: I'm using split views, and 10.in-addr.arpa. exists only in the
'internal' view. I'm doing nsupdate from "server.nl2..."
itself.

Alvise Nobile