My Supercache page URLs incorrectly contain /supercache/

Hi:

I installed Supercache 0.9.9.3 on a client's site themed with Atahualpa 3.46. My SuperCache page URLs incorrectly contain /supercache/.

I also repopulated .htaccess with rules from the current Supercache release. I did a diff between my .htaccess and the rules displayed under View Mod Rewrite Rules in the Supercache control panel. The rules are in .htaccess correctly. Same thing for cache/.htaccess. The Supercache control panel test says that it is working.

This WordPress forum thread suggesting disabling all plugins: Supercache appended to URL
http://wordpress.org/support/topic/p...rl-1?replies=9

I did that and the problem remains. This therefore suggests that the problem is with my configuration or that it involves a Supercache incompatibility with Atahualpa, so I am posting this problem here.

More details:
When logged in as admin, a specific page URL displays as:
http://www.limitstogrowth.org/articl...terrible-cost/

When not logged in, the same page URL displays as:
http://www.limitstogrowth.org/wp-con...ost/index.html

Both pages contain in the source:
<!-- Cached page generated by WP-Super-Cache on 2010-08-14 17:00:39 -->



Suggestions?

Perhaps I should throw out Supercache and go with basic WP Cache or with Cache 2?

Thank you very much,

Fred