Thanks very much for investing your time fixing my problem.
- I fixed the errors and now it checks out
- I put the W3C Validator in my bookmarks and will use it henceforth (I know this should have been automatic for me, but I am still learning)
- Interestingly, the W3C Validator missed the real problem, noted in the replies above yours. Because I transposed a "]" and a "--" a comment tag was not closed. Some browsers tolerated this error; others treated all my content as a huge comment!