Help with collision model

I’ve created a collision model but in HLMV, I get this thing in between the feet as shown here:
Imgur
I’ve tried looking through my model but couldn’t find what was causing it.
Any help to try to remove it would be appreciated.

Here’s the link to the collision model file:
https://drive.google.com/file/d/0B877WXdKRsbNZDBPR2dCMzBWSUU/view?usp=sharing

Since I’m new to modeling, an explanation to what caused it would be nice.

Does the model have bones? If so, did you weight the leg to it correctly?

That doesn’t look like a good collision mesh at all. Did you make it or just use your original model?

I used the original model and made the collision model by cutting it up. I know there are better ways to make a collision model but this way’s worked alright for me so far.