Thank you for the feedback.
I understand you raising the issue of page errors and will address them.
However, The page (and site) has not been changed significantly for a long time, so I am going under the assumption that those errors have always been there.
They have not harmed our ranking in the past.
Our site has always ranked well for our desired terms.
We only made two changes recently that I would anticipate causing the drop in rankings.
One was the changes we made as previously described above.
The other was that we submitted our site to several directories.
These were smaller directories.