I have post indexer v3.0.4 on wpms 3.5.1. My error log

Hi, I have post indexer v3.0.4 on wpms 3.5.1.
My error log is getting full from errors like the following, due to high traffic site.

Duplicate entry '%ce%b4-%cf%84%ce%ac%ce%be%ce%b7' for key 'slug' \xce\xb2\xce\xac\xcf\x83\xce\xb7\xcf\x82 \xce\xb4\xce\xb5\xce\xb4\xce\xbf\xce\xbc\xce\xad\xce\xbd\xcf\x89\xce\xbd WordPress \xce\xb3\xce\xb9\xce\xb1 \xce\xb1\xce\xaf\xcf\x84\xce\xb7\xcf\x83\xce\xb7 INSERT INTOwp_network_terms(name,slug,term_group) VALUES ('\xce\x94\\' \xcf\x84\xce\xac\xce\xbe\xce\xb7','%ce%b4-%cf%84%ce%ac%ce%be%ce%b7',0) \xce\xb1\xcf\x80\xcf\x8c post_preview, wp_create_post_autosave, wp_update_post, wp_insert_post, do_action('save_post'), call_user_func_array, postindexeradmin->index_post, postindexermodel->index_tax, postindexermodel->insert_or_get_term, m_wpdb->query, referer: http://blogs.sch.gr/myblog/wp-admin/post.php?post=236&action=edit

I guess its a bug of post indexer, but can't locate it in order to fix it.
Can you please "ping" the developer about it?

Thanks in advance.
Lena