title: Emacs failure in loading charset map when saving file with unicode
body: <p>I created an ordinary text file on Windows 7 64-bit using gnu emacs 23.3.1. I can edit the file with other programs such as LinqPad (the file happens to be a linqpad script, extension .linq). Everything is fine until I put a Unicode character in the file, a character such as the greek letter λ (lambda). I can input the letter in emacs and it displays correctly. However, emacs refuses to save the file, reporting the following error</p>
  
  <pre><code>Failure in loading charset map: 8859-7
  </code></pre>
  
  <p>If I input the λ in LinqPad, emacs will read and display them, but will not save the file.</p>
  
  <p>I just noticed that Notepad++ has other unexpected behavior with this file: it does not display the λ's, but instead pairs of odd characters such as Î». That is fitting to an untuition (pun intended) that the unicode chars are being stored as pairs. So it looks like this is a kind of ambiguous situation (storing unicode in text files), but it also looks like linqPad and visual studio "do the obvious thing."</p>
  
  <p>I want to use emacs because it's the only program that I have that reflows sequences of commented lines (lines after //, reflows them with Alt-Q), and I want to use greek characters in my comments because I'm describing a mathematical program.</p>
  
  <p>I'll be grateful for advice and answers.</p>
  
  <p>UPDATE: some advice in other questions said to try M-x describe-char, also bound to C-x = ; both of those give me the same failure message as above, so they're on the right track, just not answers.</p>