Hi,
I purchased exactly the same kit and had the same problem.
The problem appears to be that this combination does not work in low light on a K10D. I found that if you manually focused to near the focusing point it would work fine, or if conditions were not dull everything would be fine.
Otherwise the focusing motor whirred and nothing happened.

I have found that the lens is excellent quality and very sharp, even with the teleconverter on. I would suggest switching the shake reduction off if you use it on a tripod.

Hi

I live and work in that area so would be interested in meeting you, and going on some of the photo trips you describe.

Do get in touch.

Tim