TMS FMX RichEdit j 'saves files in .rte format and it is impossible to reopen .
Message error   "forma incorecte flows"

french to english translation google

Are you 100% sure this file is in .RTE format?  Did you save with TMSFMXRichEditor.SaveToFile('filename.rte'); ?
Can you try to open it in Notepad and verify it isn't a plain text file or HTML file?