>I verified that the coordinates that are being passed correspond to the position I want on the top level form. Desktop is set to false and the child form is set to a 1 (in top level form).

Say you want the Child form to half-way down the parent form, try pasing it this:

do form childtest with Thisform.top + thisform.height/2, Thisform.left + thisform.width/2

This works for me with no other properties set than Top Level (for parent) and In TOp Level (for Child)