Problems with the motility of an NPC in the source engine. Thread

Good evening, ladies and gentlemen.

Forgive me if it is inappropriate to ask for assistance or guidance on this particular area of the forums, but I didn't see any other area that I felt it fit into. With this being the 3D modelling and animating subforum, I'm operating under the assumption that this includes the writing of Valve .QC compilation files, and I have thus concluded that it probably makes the most sense to post it here.

I have been working for a few days on creating and implementing a zombie model for use in an alien swarm mod titled "zombie swarm." The model is intended to replace the standard alien drone in the game, but since the alien drone skeleton is hardly humanoid, this has meant that all of the animations have needed to be redone. Animating is not my problem, however, getting all of the pieces back together into a working .mdl model seems to be. (at least, in this case.) (A link to Zombie Swarm's ModDB page. I confess that it's rather bare, but I never was much of a publicist: Moddb.com _

With much trial and error, I have managed to get the model to compile successfully with no errors, but have since been plagued by a number of in-game bugs which I have been successfully fighting one by one for several days, but this particular bug has me stymied and I don't know what I'm supposed to do to fix it. My usual resources (such as the valve developer wiki and repeated google searches) have thus far been unhelpful. I was hoping that you good ladies and gentlemen of the Moddb Community would be willing to lend me your expertise and experience and help me get my zombies functional in the game engine.

The problem appears to manifest during any animation that requires the model to actually move from it's starting point. Whether this is crawling, walking or running, it faces the same problem. The model manages to take two steps (one complete loop of the 'walk' cycle,) and then it is snapped back to it's original starting point like a whipcrack. Frozen on the spot, it just takes a couple of steps forward, then goes back in a blink, and then repeats.

Upon closer inspection in the HLMV, I noticed that the root bone was not moving from it's original starting point. It simply hovered there as if it had been set as a rigid bone or something, but upon reviewing my QC time and time again, I fail to see where that might have taken place.

Assuming that I had made a mistake in the export of my animation files, I returned to Blender3D, the software that I used for the animation of my zombie, and to my confusion, noticed that the root bone moved seamlessly with the rest of the model in exactly the manner it was supposed to. So why wasn't it doing it in the HLMV?

I attach this visual aid to give you an idea of what I mean:
S9.postimg.org
(I am aware that the texture is not present. This is simply because it has not yet been implemented.)

I also attach my zombie QC file, which I will admit is a bit untidy, but is based heavily upon the QC of the alien drone that is available as part of the Alien Swarm SDK. Most of the alterations were simply me removing elements of the QC that were not needed, such as the alien jumping sequences (since zombies do not jump) and the alien wall-climbing sequences (since zombies do not climb).

Freetexthost.com
I should also add that adding a further six "0.000000" to the end of the "root" definebone function, as per the other definebone functions, has no effect. (In other words, making it look like this:
$definebone "root" "" -0.000005 -0.533615 38.566917 1.570796 -0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000"
causes no change.)

The affected animations are all those marked with LX LY.

I'm currently totally at a loss for what I should do, and I feel that I could spend an eternity just chipping away at the problem and still get nowhere. Therefore, I'm turning to the greater wisdom of the collective and asking all of you for your assistance in helping me to get this model to work properly. I appreciate any and all assistance that any of you might be able to give.

Thanking you humbly for your assistance, time and patience,
-Kenny Gardner.