bind-9.10.0pl2 rrl issue?

[6bone%6bone.informatik.uni-leipzig.de@localhost]

I updated from bind99 to bind910. The bind910 doen't accept the rrl 
configuration.

The following configuration will be accepted:

        rate-limit {
                responses-per-second 50;
                window 5;
        }

but the following configuration is rejected:

        rate-limit {
                responses-per-second size 4000 5;
                window 5;
        }


the logfile reports:

Jul 25 13:32:55 augate named[5689]: starting BIND 9.10.0-P2
Jul 25 13:32:55 augate named[5689]: built with '--without-libxml2' 
'--enable-ipv6' '--enable-threads' '--with-readline' '--with-libtool' 
'--sysconfdir=/etc' '--localstatedir=/var' '--disable-openssl-version-check' 
'--with-openssl=/usr' '--with-python=no' '--prefix=/usr/pkg' 
'--build=x86_64--netbsd' '--host=x86_64--netbsd' '--mandir=/usr/pkg/man' 
'build_alias=x86_64--netbsd' 'host_alias=x86_64--netbsd' 'CC=gcc' 'CFLAGS=-O2 
-pthread -I/usr/include' 'LDFLAGS=-pthread -L/usr/lib -Wl,-R/usr/lib 
-Wl,-R/usr/pkg/lib' 'LIBS=' 'CPPFLAGS=-I/usr/include'
Jul 25 13:32:55 augate named[5689]: 
----------------------------------------------------
Jul 25 13:32:55 augate named[5689]: BIND 9 is maintained by Internet Systems 
Consortium,
Jul 25 13:32:55 augate named[5689]: Inc. (ISC), a non-profit 501(c)(3) 
public-benefit
Jul 25 13:32:55 augate named[5689]: corporation.  Support and training for 
BIND9 are
Jul 25 13:32:55 augate named[5689]: available at https://www.isc.org/support
Jul 25 13:32:55 augate named[5689]: 
----------------------------------------------------
Jul 25 13:32:55 augate named[5689]: found 8 CPUs, using 8 worker threads
Jul 25 13:32:55 augate named[5689]: using 4 UDP listeners per interface
Jul 25 13:32:55 augate named[5689]: using up to 4096 sockets
Jul 25 13:32:55 augate named[5689]: loading configuration from '/etc/named.conf'
Jul 25 13:32:55 augate named[5689]: /etc/named.conf:28: expected number near 
'size'
Jul 25 13:32:55 augate named[5689]: loading configuration: unexpected token
Jul 25 13:32:55 augate named[5689]: exiting (due to fatal error)

line 28 is: responses-per-second size 4000 5;


Any ideas what could be the problem?


Thank you for your efforts

Regards
Uwe