Thanks for that, good to know.. So it would therefore seem that the issue is related directly to your application design and not the Tobii Interaction API itself.
Accordingly, my suggestion would be to see how much of the code from your existing project you can transfer to operate on top of the Tobii produced c# sample which works. I am afraid that the detailed debugging of user project code is beyond the scope of this forum.
Please try it out and let us know how you get on.