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Hi Mark!

Try this and see if it fixes the problem:

1) Under the blog's Dashboard, go to edit any page (Pages -> Edit -> <pick any page> ).
2) At the top right corner of the screen, look for a drop-down menu called "Screen Options" -- click that.
3) Under "Screen Layout", next to "Number of Columns", make sure that "2" is selected.

Hopefully that will clear up the problem and return your "Publish" section to its proper place. If you are still having difficulties getting it to appear, let us know.
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I thought I'd tried this, but I guess not - because it worked! Thanks for the help everyone. Mark

In the problem site, I don't have any posts, just pages. In my other site which is OK I have both pages and posts.

I just tried to create a post for the problem site, but the 'Publish' section/option dialogue box is missing from that as well. I also tried to create a new page as well, but it's the same thing. The 'Publish' section doesn't appear. I have no way to publish new posts or pages, and no way to update existing pages.

I guess raincoaster is right - something has gone horribly wrong, so I'll contact support. Thanks for your input. Much appreciated! Mark

Or did you change the structure and create a page structured blog, instead of a post based structure, like a mock website?
The URL for a page looks like this: http://blogname.wordpress.com/page-title/

Posts and pages are quite different. See > http://en.support.wordpress.com/post-vs-page/

2. The problem is on all (3) pages.

3. I am the sole Administrator.

4. The blog uses the 'Contempt' theme.

5. The other blog I manage is fine (http://voiceofcanada.wordpress.com). It uses the 'Cutline' theme.

6. I have tried logging in and out over several days.

Any suggestions? Thanks.