Apache AllowEncodedSlashes Issue

I recently struggled with the same problem on my Fedora 10 system. In my case the culprit was some odd redirection that I was doing in Apache. Specifically, I use a content management system (Drupal, to be exact) that within it's .htaccess includes the following redirection logic to redirect missing files to a PHP script:

# Rewrite URLs of the form 'x' to the form 'index.php?q=x'.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !=/favicon.ico
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]

It makes sense that the above only affects the PUT method since in that case REQUEST_FILENAME does not exist.

Not having the WebDAV area inside of the Drupal area, which seems like a reasonable constraint, fixes the problem.

Also, I think it is likely that SELinux would result in a different error, but it's not mentioned in the discussion above. Did you try disabling SELinux?

ps aux | egrep '(apache|httpd)' typically will show what apache is running as.

Usually you do not need to change the default user, "nobody" or "apache" are typically fine users. As long as its not "root" ;)

edit: more accurate command for catching apache binaries too