?unset? ??? where did this come from?

Hello everyone. I'm trying to create a little utility script that will check for closing HTML tags and replace if missing (so as not to mess with the rest of the document) It looks like this HTML: "some html with only a <b> bold opening tag" tags: ["<b>" "</b>" "<i>" "</i>" "<h1>" "</h1>" "<h2>" </h2> "<h3>" "</h3>" "<h4>" "</h 4>" "<h5>" "</h5>" "<h6>" "</h6>" "<h7>" "</h7>" <div> "</div>" "<font>" "</font>" "<pre>" "</pr e>" "<blockquote>" "</blockquote>"] foreach [start end] tags [if all [find HTML start not find HTML end] [insert tail HTML end]] This works fine, but the problem is I get an ?unset? included with it? Where did this come from? Or rather, how do i get rid of it? T Brownell