I upgraded a site recently from 2.7 to 2.9.1 after an attack on the site. The site is behaving fine apart from tags in the back end are now displaying the following error:
Warning: implode() [function.implode]: Bad arguments. in /var/www/vhosts/locwsinternational.com/httpdocs/wp-includes/taxonomy.php on line 781
The front of the site is displaying them, producing no PHP errors, nor does it have trouble providing results by tag sort.
I have upgraded all plugins running, tried upgrading and repairing the database using plugin tools with no success so far.
Any help on this would be great. Many thanks