Von,

I read your post before I installed my C130, and I confirm that it also does like the other posters mention, just like in real life if you leave everything at ground idle, prop levers full forward and mix levers full forward, and release the brakes, it will start to "creep" ahead.

I don't know why yours would go ahead so quickly though, unless maybe you're on a downward incline.

I notice though if I pull my mixture lever back a bit until the engines start to "growl" little, it will no longer pull forward.  There doesn't seem to be a variable lever like this in the cockpit, and I have yet to find the actual fuel condition levers, though the prop pitch levers seem to be marked as such in the VC.

I do notice if I try to pull the prop levers back in ground idle, the torque goes over a limit and the engines shut down.  I think this is accurate, but I'll have to wait until my friend gets back from deployment to ask him.  He runs on the herc crews in real life, so he'd know for sure. :)