This patch modifies the ec3_filter_posts_where function to allow tag archive pages to display ec3 events. If you keep events separate, tag archive pages will not return events because ec3 filters them out. This patch makes ec3 "tag aware" on WP 2.3 or later installations. I don't have a WP 2.2 testing platform so I added a version check so WP 2.2 users would not error out. Not sure if it's needed.