I have installed CFX 11 on a Windows XP 64-bit platform. I can run the solver in serial and in PVM local parallel modes, but when I try to use the MPICH2 local parallel mode the solver stops with the error:
The ANSYS CFX solver could not be started, or exited with return code 255: . No results file has been created.
Unlike MPICH where the MPICH service only needs to be registered for distributed parallel, the MPICH2 service must be registered for both local AND distributed parallel. So you will need to issue the commands:
in a Command Prompt window created from the CFX 11 Launcher using the option Tools > Command Line.
This is described on page 63 of the ANSYS, Inc. Installation Guide for Windows, Release 11.0.