Erreur à la lecture

int openWaveFile(char* file) {
	unsigned long size;
	errCode = 0;

	/*Does the file has the .wav extension?*/
	if (!strstr(file, ".wav"))
		ERR(1);
	
	/*open file for reading*/
	if ((fp = fopen(file, "r")) == NULL)
		ERR(2);

	/*get size*/
	fseek(fp, 0, SEEK_END);
	size = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	/*allocates the whole buffer*/
	if(!(buffer = (unsigned char*)malloc(size * sizeof(unsigned char))))
		ERR(5);

	/*read the whole file and close it*/
	if (fread((void*)&buffer, sizeof(unsigned char), size, fp) != size)
		ERR(3);
	fclose(fp);

	/*header's at the very beginning*/
	header = (struct WAV_HEADER *)buffer;

	/*Then check it!*/
	if (header->declare.riffTag[0] != 'R' ||
		header->declare.riffTag[1] != 'I' ||
		header->declare.riffTag[2] != 'F' ||
		header->declare.riffTag[3] != 'F') ERR(4);
	if (header->declare.waveTag[0] != 'W' ||
		header->declare.waveTag[1] != 'A' ||
		header->declare.waveTag[2] != 'V' ||
		header->declare.waveTag[3] != 'E') ERR(4);
	if (header->header.formatBlockID[0] != 'f' ||
		header->header.formatBlockID[1] != 'm' ||
		header->header.formatBlockID[2] != 't') ERR(4);

	data_pos.buffer = buffer;
	data_pos.bufferSize = size;
	data_pos.bytesPerSample = header->header.bytesPerSample;

end:
	if (fp) fclose(fp);
	return errCode;
}