Errors under PHP5.4

Actually, I was wrong the difference in not in the version of PHP.

I was running one version with display_errors = on

So it is possible to see the error being generated.

Would be nice to know what is causing the error and how to fix it.

You can fix this warning by adding the following lines at the start of the get_terms() function around line 294:

if (is_string($args)) {
            $orderby = $args;
            $args = Array('orderby' => $orderby);
        }