HFSS error: Failure in assembling radiation term

hi all

i'm design antenna in HFSS,
and i find this:
Port refinement, process hf3d error: Failure in assembling radiation term.. (10:40 Mei 24, 2010)
what does it mean?
can anyone tell me..

go to DRAW--> Region and draw region around the antenna. Then select that box and Assign--> boundary--> Radiation.

This assigns a radation boundary around the object which gives the practical condition.

if you use lumped port the port should be inside the box. make sure give a 5 mil spcae from lumped port to th box. if it is wave port you needn't worry.

This MIGHT solve your problem.