Help !! HFSS simulation error

Hi

while simulation these 2 errors are coming "

1. [error] Part EquationSurface1 has negative volume.
2. [error] Acis error: "api_check_entity failed for part: EquationSurface1"

i am not able to figure out these errors. it will be of great help if anybody can figure out those errors and how to remove them...

You better post your hfss file here, need more details.