Howdy y'all.

I've recently begun to build a model of a Predator Ahnnilator from Warhammer 40k. After nearly 3 days of work or so on just the model alone I've gotten this much done. All I gotta do now is to Mirror Duplicate this highlighted area in red. Following the directions from the maya help page, I set the Translate and Rotate values to 0, and the scaling to -1 using the X position. But for some reason, I keep on getting this weird little straight line seen here. Even after undoing my problems and attempting the Mirror Geometry feature, I still get the same results.

Any suggestions or similar scenarios on how I can get out of this problem?.

EDIT:
Forgot something else. For some reason, my copy of MAYA also won't let me unparent an object.