How do I activate comments?

I have several static pages and one post page. I have turned comments OFF on all the static pages, but ON for the POSTS page and for the individual posts as well. When I look at the posts page, I see the link for comments, but when I click it, I get the dreaded 404 error.

If I turn comments ON for one of the static pages, I get the comment form when I click on comments. If I turn it OFF, I get the note “comment form closed”.

How do I turn comments ON for my posts? In DISCUSSION I have checked COMMENT AUTHOR MUST FILL OUT NAME AND EMAIL and BREAK COMMENTS INTO PAGES. I also have AN ADMINISTRATOR MUST ALWAYS APPROVE COMMENTS.

I am using a theme, but this works the same if I use my theme or I use the default classic theme. When I use the default classic theme I don’t have any widgets active, no advertizing, straight out of the box.

I am a total newbie, so there must be something obvious I’m missing.

Thanks,

Greg