Apache on Linux: .htaccess settings and cPanel
 

(edit: note-- if you want to find my question... you can actually skip all of my nonsense narration-- all the way into the first reply at the bottom. sorry-- it just took me that long to hash-out what i was trying to ask)

hello!
to be honest, i'm not sure if i've come to precisely the right place for this inquiry, so please let me know if there's a more appropriate resource. (but, from the looks of things-- i think i'm in the right spot! and the emphasis on friendliness sounds inviting. ;)

i'm lease what i believe is "shared hosting" space from a provider who is using the following (as copied from my cpanel info):

Quote:

General server information: Operating system Linux Service Status Click to View Kernel version 2.4.21-32.0.1.EL Machine Type i686 Apache version 1.3.34 (Unix) PERL version 5.8.7 Path to PERL /usr/bin/perl Path to sendmail /usr/sbin/sendmail Installed Perl Modules Click to View PHP version 4.4.2 MySQL version 4.1.13-standard cPanel Build 10.8.1-STABLE 31 Theme cPanel X v2.5.0 Documentation Click to View cPanel Pro 1.0 (RC36)

this Shared Hosting account is setup so that i can use 5 "addon" domains, which, although they don't appear to an unsuspecting visitor as a sub-folder of another domain-name, to avoid the set-up of a new control panel account (and keep cost down, i presume), the files simply reside in a sub-domain of the parent domain account (i.e. "men are from mars dot com" could be an add-on domain of "women are from venus dot com", yet the visitors would never be any the wiser (in theory)-- essentially because the DNS allows the "parking" of that add-on domain name calls to that URL are redirected to the sub-folder where the files reside, whereas the similar, "subdomain" option uses no new domain name, yet no slashes in the URL to appear blatantly as a sub-folder, but more like a sub-net mask, as in "sub-domain dot domain dot com" instead of "domain dot com-- slash sub-domain".

please allow me to clarify
 

upon re-reading my post above, i can see why i received no replies... it made abosolutely no sense! i don't think i ever even asked a question!

what this is all about-- what i was obviously unable to spit out upon my first try--- its about problems with the Error pages (404 file not found, etc). because i'm using add-on domains on a shared hosting account, i'm trying to figure out how to use the .htaccess file to send visitors to a pre-defined error page, no matter where the error occurs, they will always go to this predefined page.

for example, my understanding of .htaccess is that the result i've explained above is achieved by the following in the .htaccess file's first line:
DirectoryIndex my-singular-index.htm

so that all errors would go to my-singular-index.htm

i really already know the answer to my question from experience-- but i'm hoping for a bit of discussion about it because i don't understand "WHY" it's happening this way. so... all of this said...

What unusual behaviors might i expect from .htaccess when an add-on domain of a shared hosting account attempts to use the DirectoryIndex as in my example above?

must i simply resolve that, because of the shared nature of this hosting account, all of my error pages will default to the parent of parent root of roots (as far as my own Leased space goes), or can i manipulate .htaccess in such a way that i can in fact have dedicated error pages for my add-on domains?

Could someone define, in laymans terms, what is "Shared Hosting" versus dedicated? (only because i think it's relevant to the other two questions)

thanks!