Get exception in OS Kernel when try to open a file

I am the author of a freeware game that runs in Windows and I am evaluating Ogg 
Vorbis as a sound file format to support in the game engine. I am trying to use 
the vorbisfile API to open a .ogg file and decode it to PCM for use as a 
DirectSound buffer. Unfortunately I fell at the first hurdle :( When I try to 
use ov_open to access a file I have opened, I get an exception in kernel32.dll

The code I'm using in my test prog is:

// oggtest.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "vorbis\vorbisfile.h"

int main(int argc, char* argv[])
{
	FILE *file;
	OggVorbis_File vf;

	if ((file = fopen("test.ogg", "rb")) == NULL)
		return -1;

	if (ov_open(file, &vf, NULL, 0) < 0)
		return -1;

	ov_clear(&vf);

	return 0;
}


I hope you can answer what the problem is or I won't be able to add this 
support :/