QUICK'N'DIRTY FIX FOR WORDPRESS 2.3 USERS UNTIL THE NEW VERSION IS ROLLED OUT.
WordPress 2.3 users must change the following in the amt_get_all_categories function:
$cat_field = "cat_name";
with:
$cat_field = "name";
Also substitute the following:
$wpdb->categories
with:
$wpdb->terms
Big thanks to all and especially Rick for pointing out the problem and the fix and Barmala for the solid code contribution.
A new version of the plugin is on the way. (Unfortunately I do not have much free time at this period of the year, so it might take a few days)
Also, if you have any ideas, thoughts etc about how the inclusion of the newly added WordPress feature, tags, should be implemented into Add-Meta-Tags, please feel free to post them.
Thanks