Device Driver Deleopment

[Bob Pickles]

Hi 

Looking for some help with FreeBSD 5.1, I am new to this but I am 
fairly quick to learn.

Problem that I am having, is that in my device driver, it see's my PCI card, but when 
I call make_dev the system hangs, then resets.

If I try to use mknod, then it fails also. Looked at the /dev mount and even devfs fails.
Is there some form of protection here that I don't know about?
How can I create a device on /dev?

Thanks

Bob Pickles