Negative extrusion refuses to stick!

[seismicsource]

I have a model in which we want to make lighter than the prototype turned out to be. In order to acomplish this i am removing a chunk of the metal in the lid(images attatched. I have completed the sketch seen in red and extruded it to prove that the loop is complete but when I try to reverse the extrusioni to cut from the lid dragging down the arrow as an example, it turns the effected area a darker red than normaly seen when you cut something. When I let go of the left mouse button it pops back up to the original surface having no effect and refuses to go benieth it and when I apply I get the error seen at the bottom of the attatched image. I do this sort of cutting often instead of digging down to the root sketch then dealing with the ripple effect of the changes we want to make.

[blair]

Can you post the offending part.

[seismicsource]

Here is the lid.

[Paul-Mason]

Your problem lies in the sketch where you go around the bolt holes instead of a angle at the point where the profile goes around  apparent edge of the bolt holes and joins at a point use a fillet instead  that is where the profile is self intersecting.

[JDMather]

Why are there no dimensions in Sketch1 (the part isn't manufacturable to the geometry size you modeled, for example 4.4290101" on one of the sizes, this doesn't appear to convert to a mm size either)?