Memory allocation problem in a module with fedora core 6 on ppc

Hi,

I'm running fedora core 6 (2.6.17.7)  ppc64 and I'm trying out a module
that works perfectly OK on the same kernel version on intel.
Here's the module:
http://www.captain.at/howto-linux-device-driver-mmap.php

It fails in skeleton_init_module itself in while allocating memory (if i
comment out the memory allocation and corresponding deallocation, insmod
works ok). It throws up a message during insmod:
unable to handle paging request  at addresss xxxxxxxx
and the machine is no longer usable and I've to do a hard reboot.

I'm trying it out on a Power 5  server with nearly I GB RAM and a single
            1.5 GHz processor with SMT enabled.

Am i missing something obvious here?

Thanks in advance for any help,

Vijay