What do I need to put in my .htaccess file?

First make sure mod_rewrite is enabled on your server (ask your host).
If yes, then make your .htaccess file writable = usually it means chmod 666.
Try to set your permalinks.

If your .htaccess is not writable, doesn’t WP display (at the bottom) the code for it when you try to update the Permalink settings?

I made my .htaccess unwritable and it gave me the code that I need to put in the file. I inserted that code, but the redirects still don’t work. Does this suggest that mod_rewrite is disabled?

I’ll check with my host, but what’s the best way around this if I don’t have mod_rewrite access?

OK, this was the reply that I got from my webhost:

While we do support .htaccess files, much of the mod_rewrite functionality is not available.

However, you can use Zeus rewrite rules which work in a very similar way. For example, a mod_rewrite rule of:

RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^[^/]*\.html$ index.php

Would convert to:

match URL into $ with ^[^\/]*\.html$
if matched then
set URL = index.php
endif

This should be placed in a file named rewrite.script in your web directory.

Bearing in mind that this is the htaccess code that WP generated for me:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

…what do I need to put in the Zeus file? I tried copying their example exactly, but that didn’t work.

I’m having the exact same problem. Looks like this page might be helpful: https://gallery.menalto.com/node/32467

I haven’t had a chance to adapt what’s on that page (it’s about a similar problem for some photo gallery app) to match WordPress yet, but will post back here if I can get it to work.

This should prove useful: https://drupal.org/node/46508

While it’s not a perfectly exact match, it should be a lot more straightforward to modify this into a working script for WordPress.