Problem using Trim Tool

[micah-1]

I am having trouble using the Trim tool to trim a NURBS surface. After having created a curve by intersecting the surface, I want to trim the unwanted area by using the trim tool. When I select the surface and bring up the trim tool, the area is then deselected and I get the warning message: Trim: changed to keep originals on; curves on surface have construction history with the dependency on the surface itself. In short, I am unable to use the trim tool on the surface. Any ideas on what may be going wrong?

[xcomb]

u can do several things clean history first may not help
second your curve probably not closed or not intersecting try to snap if u have more curves attached to each other fill them with free form fillet depends on situation, that should fix your issue