textBuffer.fromFile(filename, FileEncoding::UTF8); fails

hi,

I am trying to read file  using Textbuffer class. If I indicate no encoding it works. But when I indicate FileEncoding::UTF8 it do nothing. Nothing is read. What's wrong?

TextBuffer                      textBuffer = new TextBuffer();

 ok = textBuffer.fromFile(filename, FileEncoding::UTF8);

it always returns false.