Try this,
line 861 in pp-inc.php should read (changes in bold):
$posternav .= "<a href=\"{$Globals['maindir']}/$whoami.php?cat=$cat&si=$si&page=1&sort=$sortparam&perpage=$perpage&password=$password&ppuser=$ppuser&
what=$what&name=$name&$whenterm=$whenterm&sl=$sl\">1</a> ... ";
line 872 should read:
$posternav .= "<a href=\"{$Globals['maindir']}/$whoami.php?cat=$cat&si=$si&page=$p&sort=$sortparam&perpage=$perpage&ppuser=$ppuser&
what=$what&name=$name&$whenterm=$whenterm&sl=$sl\">$thispage</a>";
line 880 should read:
$posternav .= " ... <a href=\"{$Globals['maindir']}/$whoami.php?cat=$cat&si=$si&page=$pages&sort=$sortparam&perpage=$perpage&ppuser=$ppuser&
what=$what&name=$name&$whenterm=$whenterm&sl=$sl\">$pages</a>";