_bstr_t help needed

[Ita_c]

Hi all ,
could anyone please help ,
I am keeping getting app crashes with my app
I suspect the following code
Could anyone have a look and help ,
In addition , could any one explain what are the diffrences between the _bstr_t constructor , and if I have to free them ?

Thanks very much

BOOL CMSInterface::ConvertBSTRtoCharWithoutTerminator(BSTR i_sStr,char* o_Str,long *o_Length)
{
	bool retVal = true;
	_bstr_t bstrObj(i_sStr, FALSE);
	*o_Length = bstrObj.length();
	
	long lLen = WideCharToMultiByte(CP_ACP, 0, i_sStr,(*o_Length-2), o_Str, *o_Length, NULL, NULL);

	
	if(lLen)
	{
		*o_Length-= 2;
		retVal = true;
	}
	else
	{
		*o_Length =0;
		retVal = false;
	}
	
	return retVal;

}