I am getting the error the selected sketch contains several open profiles or some geometry used for contruction. You must specify the construction geometry to solve the profile ambiguity. do you want to use the selected sketch anyway
If your wireframe is in a sketch you can try using "Sketch Analysis"? It is in the "Tools" tool bar. This should tell you where the openings are in your sketch.
Here's another 'trick' that I learned the hard way when I first started using sketcher and had the same problem with open profiles:
Look for a toolbar called SKETCH TOOLS - it has 4 icons with the left one being a blue grid with an orange dot. Activate the two icons on the right (make them orange) so you automatically get Geometric Constraints and Dimensional Constraints. Doing this, and ALWAYS doing a sketch analyis really helped me.
Concerning the other two icons in SKETCH TOOLS: SNAP TO POINT is personal preferenced (I don't use it), and CONSTRUCTION ELEMENT can be used when you know you want to create several construction lines or points.