I have a local install on my wamp server with the path:
I have moved this install to the live server with the same path structure:
When I browse to mydomain/beta/abc/001 , I get a 'server error' page - I can't access /admin either. Interestingly the base tag is still referencing localhost??
The RewriteBase '/beta/abc/001' in my htaccess is still the same, so everything should work as the path is still the same. I have also created a new db and imported the data from my local db and updated the settings in mysite/_config.php
The only other way is doing a fresh install on the live server into the sub directory and start again, but I would like to avoid this if possible.
RewriteBase should be related to URL in your browser. For example if URL is http://localhost/myProject/ then RewriteBase should be equal to '/myProject'.
When you move to PROD and URL is similar to http://myproject.com/myProject/ - leave RewriteBase untouched. Of course if live site URL is like http://myproject.com/ - you should adjust RewriteBase to '/' - works for me.
Probably you've uploaded your project with some cache files etc. If so, log in via SSH (putty for example) and flush cache from terminal level.
php ./framework/cli-script.php dev/build "flush=all";