bind9 doesn't bind to IPv6 interfaces

Binary package hint: bind9

Bind 9.5.0 doesn't bind to IPv6 interfaces.

excerpt from named.conf:

options {
        directory "/etc/bind";
        allow-recursion { 212.21.92.192/28; 10.0.0/24; 127.0.0.1; 2001:6f8:1101::/48; };
        listen-on { 127.0.0.1; 212.21.92.196; };
        listen-on-v6 { 2001:6f8:1101::2; };
};

ip addr show dev eth0:

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:60:6e:00:00:13 brd ff:ff:ff:ff:ff:ff
    inet 212.21.92.196/28 brd 212.21.92.207 scope global eth0
    inet6 2001:6f8:1101:0:260:6eff:fe00:13/64 scope global dynamic
       valid_lft 2591996sec preferred_lft 604796sec
    inet6 2001:6f8:1101::2/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::260:6eff:fe00:13/64 scope link
       valid_lft forever preferred_lft forever

syslog:
Aug 14 07:11:18 oban named[14505]: starting BIND 9.5.0-P2 -u bind
Aug 14 07:11:18 oban named[14505]: found 1 CPU, using 1 worker thread
Aug 14 07:11:18 oban named[14505]: loading configuration from '/etc/bind/named.conf'
Aug 14 07:11:18 oban named[14505]: the working directory is not writable
Aug 14 07:11:18 oban named[14505]: no IPv6 interfaces found
Aug 14 07:11:18 oban named[14505]: listening on IPv4 interface lo, 127.0.0.1#53
Aug 14 07:11:18 oban named[14505]: listening on IPv4 interface eth0, 212.21.92.196#53
Aug 14 07:11:18 oban named[14505]: default max-cache-size (33554432) applies

I have installed Ubuntu 8.10, see below for installed bind package.

bind9:
  Installed: 1:9.5.0.dfsg.P2-1
  Candidate: 1:9.5.0.dfsg.P2-1
  Version table:
 *** 1:9.5.0.dfsg.P2-1 0
        500 http://de.archive.ubuntu.com intrepid/main Packages
        100 /var/lib/dpkg/status