Can anyone help me build a webcam device driver?

I've installed Fedora 6 (kernel 2.6.18-1.2798.fc6) on my Acer Aspire 5570 laptop.
It's got an Acer Orbicam webcam on it.I am trying to build a device driver for it as it does not work on its own in Linux.

I've first tried to build a simple "hello world" module as a driver.
Here are the things I did:

1. Installed kernel-devel-2.6.18-1.2798.fc6.i586 as

yum install kernel-devel-2.6.18-1.2798.fc6.i586

2. Then I gave a command

ln -s /usr/src/kernels/2.6.22.14-72.fc6-i586 /usr/src/linux

3. Wrote a module as hello.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
MODULE_LICENSE("Dual BSD/GPL");
static int hello_init(void) {
printk("<1> Hello world!\n");
return 0;
}
static void hello_exit(void) {
printk("<1> Bye, cruel world\n");
}
module_init(hello_init);
module_exit(hello_exit);

Saved it in /root

4. Saved the same code as hello.o

5. Wrote a "Makefile" as

obj-m := hello.o

6. Issued make command as

[root@localhost ~]# make -C /usr/src/kernels/2.6.22.14-72.fc6-i686 M=$PWD modules

It compiled as

make: Entering directory `/usr/src/kernels/2.6.22.14-72.fc6-i686'
CC [M] /root/hello.o
Building modules, stage 2.
MODPOST 1 modules
CC /root/hello.mod.o
LD [M] /root/hello.ko
make: Leaving directory `/usr/src/kernels/2.6.22.14-72.fc6-i686'

7. Then I loaded hello.ko as

[root@localhost ~]# insmod hello.ko
insmod: error inserting 'hello.ko': -1 Invalid module format

This was the error message that i got.
Now I wanna know if anyone can help me solve this problem and help me build a webcam device driver.