Thanks moshu! I replaced
and the next/prev links are now functioning as expected.
The site in question is hosted on a virtual server with Dreamhost. There is another WP blog on this server that is using
without error. This blog is is associated with the "master user" on the account. The blog where the next/prev weren't working was also under this same user. So, I imagine the virtual nature of this second account is where the problems were with using the category permalink structure. Can an Apache head explain that out a bit more so I understand this more clearly?
Also, I used %post_id% because I read somewhere that this would be better for performance. Can anyone explain why that is?
Lastly, it would be great it the Permalink section in the Codex was updated to include this info about %category% not always working. I found a number of unanswered posts in the forum about next/prev link problems, some of which might be related to my issue.
Thanks again, moshu!