URL sanitizer: disabled uppercase letters in URL hex character codes (it was causing conflicts with the Windows/Apache 2.2 alt namespace separator). Thanks Techokami for finding and reporting this bug.
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>{#paste.paste_word_desc}</title>
<script type="text/javascript" src="../../tiny_mce_popup.js"></script>
<script type="text/javascript" src="js/pasteword.js"></script>
</head>
<body onresize="PasteWordDialog.resize();" style="display:none; overflow:hidden;">
<form name="source" onsubmit="return PasteWordDialog.insert();" action="#">
<div class="title">{#paste.paste_word_desc}</div>
<div>{#paste_dlg.word_title}</div>
<div id="iframecontainer"></div>
<div class="mceActionPanel">
<div style="float: left">
<input type="submit" id="insert" name="insert" value="{#insert}" />
</div>
<div style="float: right">
<input type="button" id="cancel" name="cancel" value="{#cancel}" onclick="tinyMCEPopup.close();" />
</div>
</div>
</form>
</body>
</html>