The FLX file format of the programs FelixCAD and PowerCAD is only supported in the ARES Commander Windows version. Here it is still possible to import and export FLX files. The FLX format will be not maintained in the future and file format support ended with version FLX 7.0.
Under Mac OS and under Linux, the FLX file format is not supported. In this case you can only convert your files under a Windows version prior to and in order to use the files in this platforms. If you still use PowerCAD Pro 7 then the files can be converted over the integrated batch processing to the DWG-format.