Signing of drivers

Hi
I am trying to create a cat file for some drivers we have.
I have created the following cdf file:
----
[CatalogHeader]
name=microncam.cat

[CatalogFiles]
miusb2.inf=miusb2.inf
miusb2.sys=miusb2.sys
--- END
The makecat.exe file is in the same dir as the 2 files I want to create a
cat with.
The problem is the first file e.g. miusb2.inf gets processed but regardless
of which file is on the second line e.g. if I switch the 2 lines I get the
following error:
NOT processed: unable to find file path for member (miusb2.sys)

Any ideas?

Cheers