table "mangling" is missing, but she shouldn' t

Hello
I have a linux box , linux-2.4.26 with netfilter (and iptables 1.2.9) built in the kernel, with the mangling option. There aren' t any modules compiled. All is builtin.

"iptables -t mangle -L"
gives :

iptables v1.2.9: can't initialize iptables table `mangle': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded.

and :

"cat /proc/net/ip_tables_names" gives

nat
filter

I have not set any rules for the moment, just activated IP-forwarding with "echo 1 > /proc/sys/net/ipv4/ip_forward"

What can be the problem ?

Thanks in advance.
Regards.

Axel