Audio Glitch

Hi
I was experimenting with a simple practice piece with the Classical Guitar sounds and when I came to export it to audio, either in 16 or 24 bit, there is a glitch or double note that is not there if I listen to the piece playing from the score itself. I tried exporting to Audio several times and it is always the same. There is about a 3 bar beginning that loops then plays through and on that first loop there is this kind of double note or some thing that does not belong there and is not in the score.
Does anyone ahve any advise please. I am using Notion to help teach my seld music etc.
Thanks
Mike
I was experimenting with a simple practice piece with the Classical Guitar sounds and when I came to export it to audio, either in 16 or 24 bit, there is a glitch or double note that is not there if I listen to the piece playing from the score itself. I tried exporting to Audio several times and it is always the same. There is about a 3 bar beginning that loops then plays through and on that first loop there is this kind of double note or some thing that does not belong there and is not in the score.
Does anyone ahve any advise please. I am using Notion to help teach my seld music etc.
Thanks
Mike