Hfss communication failure error

Hi,

I receive the next error, can anyone know what is the problem ?

HFSSDesign1 (DrivenModal)
[error] Communication failure. System error no: 109, error description:Unknown error (3:23:18 PM ינואר 09, 2013)
[error] Communication failure. System error no: 109, error description:Unknown error (3:23:19 PM ינואר 09, 2013)
[error] Fast sweep setup, process hf3d exited with code 100. (3:23:19 PM ינואר 09, 2013)
[error] Communication failure. System error no: 232, error description:Unknown error (3:23:19 PM ינואר 09, 2013)
[error] Unable to create child process: hf3d. (3:23:19 PM ינואר 09, 2013)
[error] Simulation completed with execution error on server: Local Machine. (3:23:19 PM ינואר 09, 2013)