Buggy ErrorDocument behavior in httpd 2.2.3

... and apparently earlier, too. I'm seeing lots of posts, and not spotting anything helpful in the documentation.

I've tried several cases for the ErrorDocument directive, and they break variously. (ETA: Actually, the http:// method works. Hooray!)

For the record, under httpd 1.3, the directive was
   ErrorDocument 404 /redirect/notfound.php
within a <VirtualHost, referring to a "redirect" subdirectory within the webroot.

1. Put the error document outside the webroot, such as in ../error/404.html.
   
   Directive:
   <VirtualHost>
       ErrorDocument 404 /web/sph/error/404.html
   </VirtualHost>
   
   Note - all directives are within the virtualhost context. I started to experiment with the directory context, but I'm omitting that part since the results were the same.
   
   Result:
   A standard 404 with the note, "Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request."
   
   Error_log:
   [Wed Aug 13 19:39:27 2008] [error] [client 10.0.0.246] File does not exist: /web/sph/html/asf
   [Wed Aug 13 19:39:27 2008] [error] [client 10.0.0.246] File does not exist: /web/sph/html/web
   
   Where on earth is it getting that "web" part??
   


2. Okay, well, let's try putting the errordoc directly in the webroot.
   
   Directive:
       ErrorDocument 404 404.html
   
   Result:
   It actually DISPLAYS THE WORDS "404.html".
   
   Error_log:
   [Wed Aug 13 19:42:17 2008] [error] [client 10.0.0.246] File does not exist: /web/sph/html/asf
   
   
   


3. Okay, let's put quotes around that last one.
   Directive:
       ErrorDocument 404 "404.html"
   
   Result:
   Same as above
   
   


4. Fine ... try same location, full path. With and without quotes.
   
   Directive:
       ErrorDocument 404 /web/sph/html/404.html
   
   Result:
   Same as #1
   
   Error_log:
   [Wed Aug 13 19:46:54 2008] [error] [client 10.0.0.246] File does not exist: /web/sph/html/asf
   [Wed Aug 13 19:46:54 2008] [error] [client 10.0.0.246] File does not exist: /web/sph/html/web
   


5. Screw you, httpd.


6. Okay, obviously something different is necessary. Try it with an URL.
   Directive:
       ErrorDocument 404 http://www.whereiwork.edu/errdoc/404.html
   
   Result:
   If the subdirectory was named "error", I got a warning about an impossible redirect. Since that wasn't coming from anything I'd configured, I guessed "error" was reserved for something and changed it to errdoc. At that point, I got the actual contents of the doc I wanted.
   

I'd like to understand how this directive is supposed to work, or find the bug report thereon, but I'd like much more to go home.