directshow video source filter: couldn't bind moniker to filter object (0x800401f9)

I compiled an (existing [1]) directshow source filter, then plugged it into VLC to use it and get this:

dshow error: couldn't bind moniker to filter object (0x800401f9)

dshow error: can't use device: Virtual Cam, unsupported device type

compiled using visual studio 2010 express + windows SDK 7.1

any ideas out there?

-r

code at: http://github.com/rdp/virtual-audio-output-sniffer

[1] original was "capture source filter" from http://tmhare.mvps.org/downloads.htm and his binaries actually register and work right (well, they at least start right, then they hang VLC but that's a different story).

Problem turned out that I wasn't exporting "enough" symbols from my DLL.

Once I created a def file with the right methods and instructed the linker to use it it works now.

Happy day.

(also cross linking this to where I also posted it at http://betterlogic.com/roger/?p=3107)