There are 2 small mistakes in pageNavigation.class.php file - li tag is not closed correctly - resulting in invalid xhtml.
It is located on line 124 and 146.
line 124
$html .= "\n<li><span class=\"pagenav\"> $i </span><li>";
line 146
$html .= "\n<li><span class=\"pagenav\">".$VM_LANG->_('PN_END')." »»</span><li>";
just change <li> at the ned of these lines to be </li>.
Ok,
this is fixed in SVN now.
Thanks for reporting!