Debug.Log(xxxx)

So I have a large chunk of code that I'd rather not post if possible because the problem doesn't really lie in the code.

Inside the update function I have a series of movement on command things, hold A go left, etc, it all works phenomenally. It works exactly as it should the problem comes from one single line of code.

Debug.Log (" ");

If I remove Debug.Log, the whole program goes to absolute shit, nothing works as it should, unpredictable, backwards, inside, and out. If I put Debug.Log back into the function it instantly works again.

So the question is, how the hell do I make it work without using Debug.Log or what possible reasoning could there be for this to cause problems.

I ran the code over with a friend and apart from a couple other problems he saw no reason that this line should be causing my code to break.

Any help much appreciated.