Accessing subdomains on multisite gives 404 error.

I have been searching for this error since yesterday and there seems to be a lot of posts about it, but none that have helped me. I converted my WP to a multisite installation and when add a subdomain and then access it I get a Hostgator 404 error.

I have checked everything over and over and over and can’t figure it out. Here is some info.

site link: http://mangomango.com
host: hostgator
WP installed in public_html
I believe I made the appropriate modifications to wp-convig.php and .htaccess. And I created a subdomain via c-panel named “subtest” also unter public_html.

Selecting items from the WP/sites/subtest menu gives these results:
Dashboard: Hostgator 404 error page
New Post: Internal Server Error (text below)
Manage Comments: Internal Server Error
Visit Site: Directory listing of /public_html/subtest (which I created)

Internal Server Text:
Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, webmaster@subtest.mangomango.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.
[end of Internal Server Text]

I have a feeling that it has something to do with reading the .htaccess file, but really have no idea, and have run out of things to try.

I would appreciate your help in getting this resolved,
thanks, trey