It's good of you to post that, but your instructions...

Problem solved. I had two fields of the same name in my query. Why can't Microsoft come up with more helpful error messages? Grrr.

Could you not just use the site settings to disable subscription management for all users except those you can trust? i.e. yourself.

Further to what Revenant said, if you have tables above other tables and the columns don't line up exactly, you'll get columns merging together. Use the location and width...