It that's the first line of your toc.ncx file, it's all wrong. It looks like you've just taken the header from an XHTML file and just changed the 'html' (immediately following the !DOCTYPE) to 'ncx'.
An NCX header should look like this:
Code:
<?xml version="1.0" encoding="UTF-8" standalone="no" ?><!DOCTYPE ncx PUBLIC "-//NISO//DTD ncx 2005-1//EN" "http://www.daisy.org/z3986/2005/ncx-2005-1.dtd"><ncx xmlns="http://www.daisy.org/z3986/2005/ncx/" version="2005-1">
<head>