root@OpenWrt:~# iptables -t nat -A prerouting_rule -p tcp --dport 80 -j REDIRECT 
--to-ports 8080
iptables v1.3.8: Unknown arg `--to-ports'

root@OpenWrt:~# lsmod | grep ipt_REDIRECT

root@OpenWrt:~# ls -1 /lib/modules/2.4.35.4/ipt_*
/lib/modules/2.4.35.4/ipt_LOG.o
/lib/modules/2.4.35.4/ipt_MASQUERADE.o
/lib/modules/2.4.35.4/ipt_REJECT.o
/lib/modules/2.4.35.4/ipt_TCPMSS.o
/lib/modules/2.4.35.4/ipt_limit.o
/lib/modules/2.4.35.4/ipt_mac.o
/lib/modules/2.4.35.4/ipt_multiport.o
/lib/modules/2.4.35.4/ipt_state.o

root@OpenWrt:~# opkg install  iptables-mod-nat
Package iptables-mod-nat (1.3.8-4) installed in root is up to date.
root@OpenWrt:~# 
root@OpenWrt:~# opkg install kmod-ipt-nat
Package kmod-ipt-nat (2.4.35.4-brcm-2.4-1) installed in root is up to date.

opkg install iptables-mod-nat-extra