Problem in registering new netfilter target module

Friends I'm facing a big problem trying to extend the netfilter. Somone please help me with your quick reply (any hint) as I've to meet a deadline.

My problem is that I've written a new netfilter target module and its corresponding userspace program for iptables to change the packet type of a packet. I compiled the iptables and kernel without any error and installed this new kernel (with newly compiled parameters) in my boot partition.

Next when I booted into this kernel and tried using this target it gives error "invalid argument" which I think is coming because the target module is not geting loaded (as on failure it returns EINVAL).

Now can anyone tell me what may b the problem.
I think I can summarise my problem as what can b pozbl. reasons for which any kernel module not get registered.