installing device fails

Hi,

I try to develop a driver for Win98/W2K.
I get the book "Programming the WDM " of Walter Oney which looks very
good.
This book contains a CD with a WDM wizard for VC++ 6 which generates WDM
projects.
These include a lot of the needed functions which have to be filled with
life.

I generated such a project (which includes also the INF file), comlied
it and tried to install the new driver on a Win98 System.
I’m not sure to which device class the driver belongs to, so I defined
Class=Unknown in the INF file and
FILE_DEVICE_UNKNOWN in IoCreateDevice.
I tried different Device-Classes but every time I try to install it I
get

A fatal exeption … in VXD NTKERN(0)

Any ideas

TIA
Vasili