WordPress MU

When i try to add a new category i get weird problem. New category is not added instead category with different name is added.

Following error is filed in error log:

WordPress database error Duplicate entry '1844' for key 1 for query UPDATE wp_2_terms SET term_id = 1844 WHERE term_id = 273174 made by wp_insert_category, wp_insert_term, apply_filters, call_user_func_array, global_terms, referer: http://exoticbuddha.org/wp-admin/categories.php

I'm having the same problem, as you can see here: http://mu.wordpress.org/forums/topic/18313?replies=3. Seems like it's a somewhat recent problem.
Do you use the plugin Simple Tags by chance?