cst bending operation failed

Hi all,
Is there anyone here already using CST 2009?
If so, i'll appreciate some help in the "Bending Sheet" option.
I'm able to bend a rectangular patch on a cylinder (meant to be a patch antenna ultimately). But I'm having troubles bending the exact same shape on a section of a cone.
The error msg is : " Bending Operation Failed (try to simplify or heal the geometry)"
Any help would be great,
10x alot.

Hi,
could u teach me how to bending rectangular patch?
if u have some notes can also share with me.
rgds,
kyg