from the fact that the path you are using for your video files starts with "\\.host" i'm guessing you are trying to run VTM from inside of a VMWare virtual machine.

The problem with trying to run a program like VTM from inside a virtual machine is that virtual machines "virtualize" the graphics processor. In other words, even if you have a really nice graphics card in your system you can't access it from inside the vm.

What this translates into is that virtual machines don't fully support direct3D and the components that VTM relies on to be able to capture and process images from a video don't work correctly (I made a post about this a while back called "VTM and Virtual Machines"... if you care about the particulars, read that).

Anyway, to get back to the point, the easiest way to fix your problem is to run VTM from your actual host machine (not the virtual machine)... assuming that you don't have a really, really bad graphics card you should be good to go.

Hope that helps

Thanks for that. I am indeed running VMWare.

Windows Media Player classic can produce the thumbnails in
much the same format as this software and doesn't have
a problem with the graphics card so i've solved the problem
by using that instead.

Thanks,
Adrian.