[CentOS] boot slow at "Applying ip6tables firewall rules"

I have a fairly vanilla install of Centos5 on a desktop box (with a 
Broadcom NetXtreme BCM5752 Gigabit NIC). When booting, the boot process 
hangs at "Applying ip6tables firewall rules" for 30-60 seconds before 
proceeding, which is annoying. I have not tried to turn off ipv6 
networking. I guess I could, but is this slowness to be expected? Is it 
waiting for some ipv6 response?

Thanks,
Dan