I've used XnView 1.91 under Windows XP to create a web page of my photos (default template, framed). In "thumb.html" XnView creates links of the form
Note the backslash after "thumb". Some servers are not tolerant enough to handle this small error, so it should become a forward slash as after "original".<a href="original/S4302404.html" target="frame2"><img src="thumb\t_S4302404.jpg" alt="S4302404.jpg" width="75" height="100"></a>