My first thought was that your software, while written by you, looks eerily similiar to those covered by defended patents (#5,845,265, #6,085,176 and #6,202,051). While I hope nothing Bad happens to you or this effort, I thought I would point this out, in case you haven't heard about this.
Thanks for your reponse thats very interesting... I was not aware of this particularly although I have heard rumours about some dodgy patent rules in the US. However i'm not sure how US patent law affects me, i'm English and based in England... Do I need to worry about US patents, what about UK ones?