I was just looking back at some of the previous posts and I see you said you are trying to implement the infoWindow inside a userControl which is not the same page as your map. Have you tried to use it inside the same page as your map? Maybe see if you can get it to work in there. If you can, then maybe that'll give you some hints. I've never tried to implement the infoWindow on a page that's not the same as my map. I'm not sure why you would want to.