QoS compilation problems Linux 2.4.22

Can anyone help with this problem?

I have a fresh download of the 2.4.22 kernel which I've compiled from
my currently working 2.4.22 kernel. The reason for using a new one is
that I want to compile QoS support into it without breaking the
working kernel.

However, when I compile the QoS modules into the kernel and do depmod
-ae I get a lot of unresolved symbols in the ppp and iptables modules.

Have I missed something out or is this a known bug?

Regards

Pete