How to correctly use this plugin?

I downloaded the plugin
http://wordpress.org/extend/plugins/tdo-tag-fixes/

I insert in sidebar.php

<div class="tags">
<?php if(function_exists('tdotf_cat_tag_cloud')) {
tdotf_cat_tag_cloud();
}
?>

<?php endif; ?>
</div>

in sidebar.

I corrected the line in tdotf.php as in was advised in forums. But nothing at all is showing. I just need the tags to be filtered by category when in category archives and single post. What am I doing wronng?

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