I've found a few problems with Fedora Core 1 kernel compilation:

To my knowledge /boot/config-2.4.22-1.2149.nptl and /usr/src/linux-2.4.22-1.2149.nptl/configs/kernel-2.4.22-i686.config are supposed to be the same (diff the 2 files and the reply is no difference) and usage of anyone of them should get you the current running kernel. Well think again. I copied the file to .config and tried to recompile the kernel but the end result is lots of modules and drivers aren't loading compared to the original running kernel (2.4.22-1.249). Here is what I did.

1. cd /usr/src/linux-2.4.22-1.2149.nptl
2. cp configs/kernel-2.4.22-i686.config .config
3. make menuconfig; make menuconfig #you have to run 2 times or else you'll get a error during make bzImage
4. make dep
5. make clean
6. make bzImage
7. make modules
8. make modules_install
9. make install
10. reboot

After rebooting into the new kernel (nptlcustom) I found out that my external usb harddisk was not detected. Why? Isn't the new kernel supposed to be the same as the original one? Upon checking I found out that lots of modules are not loaded compared to the original one (eg pcmcia, ehci-hcd, etc.) Any Idea?

i had the same problem with pcmcia!
solution: remove the folder with the symbolic links in /lib/modules/kernel-name/pcmcia when you remove it (or rename), pcmcia works again. perhaps it's the same problem with usb.

Thanks for the answer but I don't think this is the problem

I tried the one you mentioned already but it didn't help. What's worst now is, my original kernel can't even detect the external usb harddisk. Hmmmm.... must be a very big bug in Fedora. It worked earlier but after a few compilations of my kernel, now all of them can't detect my external hard disk.

Actually, my external harddisk is connected to a pcmcia card with a usb2.0 port. It worked fine in RedHat 9.0 and the first time I installed Fedora as well as the first time I recompiled my kernel. But after that all hell broke loose after my third/forth kernel recompilation. Whenever I tried modprobe/insmod usb-ohci or ehci-hcd, I get these messages:

/lib/modules/2.4.22-1.2163.nptl/kernel/drivers/usb/host/usb-ohci.o: init_module: No such device
Hint: insmod errors can be caused by incorrect module parameters, including invalid IO or IRQ parameters.
You may find more information in syslog or the output from dmesg
/lib/modules/2.4.22-1.2163.nptl/kernel/drivers/usb/host/usb-ohci.o: insmod /lib/modules/2.4.22-1.2163.nptl/kernel/drivers/usb/host/usb-ohci.o failed
/lib/modules/2.4.22-1.2163.nptl/kernel/drivers/usb/host/usb-ohci.o: insmod usb-ohci failed

I've also tried to enable/disable acpi as well as apm but to no avail. Anybody knows any work around?