[Newbie] CreateFile( "\\\\.\\\\MyDevice", ... ) failed

Every time I try to open my Device with
CreateFile(" \\.\\DevName"…) I get INVALID_HANDLE_VALUE as
result.
I added DebugPrint to every function my driver includes, but none of
them is called when I call CreateFile.
I’m using Win98 so I can’t use the tool DEVVIEW which would give me
informations about available devices.
Does someone know a tool doing this on Win98?

I Tried naming my device when registering it with IoCreateDevice, but
the same (nothing) hapens when I try to open it.

Hope someone will have an idea and can help me

TIA
Vasili