difficultone,
I suspect CBL is right on the money, that your special views are not orthographic. Orthographic means looking straight in to a view perpendicular to its principal planes such as the Front, Top, and Right. Isometric is not orthographic, nor will a rotated view be.
A simple test can be perfomed by manually adding a dimension in your drawing view of a feature you have already controlled with a dimension in its feature sketch. Can you even add the dimension to the feature? If you can is it the same value as the feature sketch? If the answer is "no" to either of these then it is pretty likely your views are not orthographic and you will not be able to define with dimensions on the drawing to the same dimensions you modeled the part to, much less be able to insert Model Items.
Stick with the Front/Top/Right views and use standard third-angle projection on the drawing. If the defauult F/T/R views do not present the part in a good view for the drawing that is easily changed by redefining which view is the F/T/R in the part.
CBL's last suggestion to post the part and drawing would make it easy for the members to see your problem and more directly help you.
- - -Updraft