[CentOS] iptables connlimit

hi,

i try use iptables connlimit,

# iptables -I INPUT -p tcp --dport 80 -m connlimit --connlimit-above 16 
--connlimit-mask 24 -j DROP
iptables: Unknown error 4294967295

where is problem ?
thanks


# rpm -qa | grep iptables
iptables-1.3.5-4.el5

# uname -a
Linux test 2.6.18-92.1.1.el5 #1 SMP Sat Jun 21 19:04:27 EDT 2008 i686 
i686 i386 GNU/Linux