Error at end of each Wiki post

Hi,

I've installed Wiki. It generally works fine, but I am getting this error at the bottom of each page:

Warning: Illegal offset type in isset or empty in /home/madetome/public_html/wp-includes/taxonomy.php on line 231
Filed Under:

It appears at the bottom of five of the six tabs: Page, Discussion, History, Edit, Create New

Many thanks in advance for your help.

Bernie