Is Gallery.htm your home page?
If so, it looks like you’re using a Frontpage template, which has added a lot of stuff to the HTML that makes your home page look for things that aren’t there. For example:
Means that you need to have a stylesheet uploaded for the page to work. Not only that, but it’s still referencing the Frontpage directories on your computer, which won’t be the same as your website’s directories.
Another example here:
It makes your page look for a file named “contents theme only.htm” in a directory named contents above your website’s directory, which probably doesn’t exist either.
You might be better off learning HTML from scratch and writing your own HTML in a basic text editor. Another alternative is to continue using Frontpage but without relying on their template files. Let me know if you need any help in those areas.