i think in widget_extended_categories.php the line case ($_avhec_version >= 3.3): your mean case ($_avhec_version >= 3.2):?
Else the require files are not found
switch ($_avhec_version) {
case ($_avhec_version >= 2.8 && $_avhec_version < 3.2):
$_avhec_version_dir = '/2.8';
break;
case ($_avhec_version >= 3.3):
$_avhec_version_dir = '/3.3';
break;
}
http://wordpress.org/extend/plugins/extended-categories-widget/