InStream.READTEXT show me the wrong data

Hello everyone,

I'm new on Dynamics NAV.
Currently, i'm working with NAV 2013 R2.
I have some synchronize problem, I explain :

I want to open a .txt file and read it. But when I read this file, it show me the wrong text.
Yesterday my text was "mon texte" and I updated it manually to "HELLO WORLD", but my code show me "mon texte".

You can see the result on attachment file.

Thanks a lot in advance for your answers.

l_Filename := 'C:\temp\fichier.txt';
l_File.TEXTMODE(TRUE);
IF NOT FILE.EXISTS(l_Filename) THEN
BEGIN
  MESSAGE('NOT FOUND');
END
ELSE
BEGIN
  l_File.OPEN(l_Filename);
  l_File.CREATEINSTREAM(MyInStream);
  MyInStream.READTEXT(l_Texte,100);
  MESSAGE(l_Texte);
  l_File.CLOSE;
END;