You have used an illegal character in your text. HTML uses the standard UNICODE Consortium character repertoire, and it leaves undefined (among others) 65 character codes (0 to 31 inclusive and 127 to 159 inclusive) that are sometimes used for typographical quote marks and similar in proprietary character sets. The validator has found one of these undefined characters in your document. The character may appear on your browser as a curly quote, or a trademark symbol, or some other fancy glyph; on a different computer, however, it will likely appear as a completely different character, or nothing at all.
Your best bet is to replace the character with the nearest equivalent ASCII character, or to use an appropriate character entity. For more information on Character Encoding on the web, see Alan Flavell's excellent HTML Character Set Issues reference.
This error can also be triggered by formatting characters embedded in documents by some word processors. If you use a word processor to edit your HTML documents, be sure to use the "Save as ASCII" or similar command to save the document without formatting information.[/b]
