Maybe the problem could be a broken/old version of the dll? (shooting in the dark).
It's weird the same dll works with other projects to load png's though. I dunno. I'll get hold of an older copy then.

Are you interested in writing some code for the game too ?
I'm still pretty new to the 3D GameDev scene, but sure, I'd like to help with coding were I can. I've been learning a lot from your Funky Cars demo, It's awesome.

Here's a render of a couple of weapons I've just finished.

In this pic there's a short bow, a long bow, and two different katana's.
The models, and the render, were made in Lightwave. Probly a little hard to see them exactly(from the smoothing, shadows, and AntiAliasing), so I'll do one up with one of your models holding them in Blender.