This conversion seems to not be possible. It appears that a .msj file is a temporary file generated when you work with graphics in Microsurvey CAD, so unsuitable for any conversion. It is likely that you convert .flx drawings only to other similar formats CAD formats via export function.
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
Usually this happens when the conversion would try to convert different types of data between each other, such as audio to image, or it is not possible because incompatibility between programs, caused by closed file formats, very limited support etc.
If you find entry that you feel is flagged as bad wrongly, please tell us in the discussion below with as much as information as possible so we can fix it.