'No such device or address' when writing to device driver

[Sam Carter <sam.w.carter@xxxxxxxxx>]

Hi all, 

I'm trying to write a simple char driver following the 'Linux Device Drivers' book from O' Reilly. My driver appears in /proc/devices and under lsmod. I've been trying to register the device fops table so I can read/write to it, however when I try to cat some data to it in /dev/myDevice I get the error 'No such device or address'. The device does appear on the list with ls /dev/.

Can anyone help me find the source of this problem? Thanks in advance. 

Sam