>>please take a look at the attachment, thats the shape, but how do i get rid of those yellow lines?

Those lines are from your construction method. Corner points tend to slice up the surface. So from your original curves, are there "seperation" points there? (Two curves joined perhaps)

If you look at the original curves and turn on show points, you can add a point on either side of those 2 points and then delete the two at each end of the line. Then when you create your surface it should be clear.

I think you may get a better/clearer answer here in a bit.

Burr