What is so hard????
One, Fedora Core kernels are 4k stack kernels and ndiswrapper may not work. A possible solution is to download, extract and build a new 16k stack kernel. The directions can be found at the Fedora-Red Hat site in the release notes. Building the new kernel is fairly easy, you only need to make one change to the configuration, disable the 4k stack option in the Kernel Hacking section if I remember correctly.
From the Fedora Site download the kernel source rpm file that matches your current working kernel (hint: type; uname -a ), an example file name (which is the latest kernel source for FC5); kernel-2.6.17-1.2174_FC5.src.rpm
The building of the kernel steps are from where the extracted/prepped source resides;
cp /boot/config-<version> .config (should be the same version # as what you building)
make menuconfig (this is where you disable the 4k stack option)
The copy command above creates the needed .config file used for building the new kernel.
Additional details/help can be found by reviewing the kernel rebuild guide;
When done reboot and try out your new kernel.
Two, it does not matter where the extracted ndiswrapper source is located, the kernel source location has to be known in order to build. If in the 'textbook' location then as root from where the extracted ndiswrapper source is located;