Though I am not certain as to exactly why, there seems to be a link between my having updated .htaccess to designate a preferred permalink and the default error documents called up. Since adding this text to the .htaccess file
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /within/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /within/index.php [L]
</IfModule>
in order to achieve a name- and date-based permalink
http://www.unpoedic.com/within/2006/03/31/sample-post/
any misfires throughout the domain, not limited to the sub-directory in which Wordpress is located, call up the Wordpress 404 file.
I also password-protected said directory while I continue to tinker. Now any prompt for 404 or 401 errors prompts for a password, because the error pages sought (the Wordpress error doc[s]) are beyond that gate. Consequently, visitors cannot even get a proper 404 error on my site; every action is interpreted as an attempt of unathorized access.
To remove the password from this directory would not solve the problem entirely; somehow the Wordpress error files are overriding my own.
___
Contents of .htaccess:
ErrorDocument 404 /error404.html
ErrorDocument 401 /error401.html
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /within/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /within/index.php [L]
</IfModule>