Trimming Problems

Hi, I'm trying to trim a lofted surface to fit a couple of nurbs cubes. I select the loft, then I select the bottom of the first cube and intersect them, placing a curve on the loft. I do the same with the second cube. In any case, when I go to use the trim tool, it says:

Warning: Trim: changed to keep originals on; curves on surface have construction history with the dependency on the surface itself.

I can't figure out what's going on. This is a total newb question, but replies are most welcome.

-Alex

What it is saying is that because there is history you may get unexpected results if you modify any of the surfaces leading up to it. Delete history