Can't access files in subdirectories of add-on domain

[belltown]

I have an add-on domain bbmap.org with Document Root public_html/bbmap.org (not redirected).

I have a subdomain bbmap with root domain belltown.x10hosting.com and Document Root /public_html/bbmap.org (not redirected).

I get a File Not Found error if I try to access files in subdirectories of my add-on domain. The error is displayed by my custom error handler for my bbmap.org subdomain/add-on domain.

So this gives a File Not Found error: http://bbmap.org/icons/phpinfo.php
But this does not: http://belltown.x10hosting.com/bbmap.org/icons/phpinfo.php
I can also access files in the bbmap.org root directory: http://bbmap.org/phpinfo.php

My bbmap.org directory, icons subdirectory and phpinfo.php files all have permissions of 755.

The only contents of my .htaccess files, both in my main domain public_html directory and bbmap.org subdirectory are:

<LimitExcept POST GET>
Order Deny,Allow
Deny from all
</LimitExcept>
AddType application/x-httpd-php5 .html .htm

So any idea why I cannot access files in subdirectories of my add-on domain?

 

[belltown]

After more troubleshooting, I've discovered that I can actually access files in subdirectories of my add-on domain EXCEPT files in my /icons subdirectory. I created an identical copy of /icons (same permissions, files, etc.), named /iconz, and was able to access ALL files in /iconz but NO files in /icons.

The only explanation I can think of is that there is something in the main Apache configuration file that is sending requests for /icons to another directory, e.g. an Alias /icons directive. This might also explain why I can access the /icons subdirectory from my main domain (it's below the root-level of my main domain's directory), whereas it as at the root level in my add-on domain.

Can one of the admins who has access to the main Apache configuration file please verify whether there is indeed an Alias /icons or other such directive preventing me from accessing my /icons subdirectory under my add-on domain's root directory?

Thanks.

[And before you mention that bumping a support request puts it to the back of the list -- I understand. I'm just trying to be helpful by giving you additional information so you don't waste too much of your time trying to troubleshoot a problem when I think I may have additional information to help you figure out what's going on]