@steveatty: I'll try your method, I followed the instructions of the newest version, and there, I can specify a slug on the plugin's options page, so I chose the romanian translation of "tags" which is taguri...
would you mind explaining a little more in details?
From the readme I understood that the tag_resutls.php file is used to show the results for a particular tag, not for the tag cloud, so I created a page template, based on my theme's normal page template, except that isntead of the_excerpt() I used mu_tag_cloud() - this page hast the slug of taguri as also specified in the mutags option page.
=> this leads to the problems described above.
the tag_results.php file just resides inside my theme folder and is used for displaying a specific tage for a certain tag, like your link above...
care to elaborate a little?
meanwhile I go test your suggestions.