Hello.

What is your cart version and template?

Hello

Did you try to restore your password via Forgotten password page?

Hello.

Possibly mod_secure prevent correct page loading please read http://docs.abantecart.com/pages/tips/troubleshooting.html#mod_security

Hello.
If your store url setting is correct this mean someone bot or person still access your store with incorrect url. It is not a big problem because your real customers will access your store with correct url

Hello.
Please check error log and share your site url

Hello.

Your question is related to Bitnami local server configuration. Nothing to do here with AbanteCart.
Anyway I think you need to find httpd.conf or htaccess.conf file in your Bitnami
and add this code
<Directory /pathtoabantecartbitnami/abantecart/htdocs/>
 
  <IfModule rewrite_module>
RewriteEngine on
# Rewrite section for retina high-res images with @2x in the end of filename base on cookie HTTP_IS_RETINA
# To emulate Retina mode on your NON-Retina display, add HTTP_IS_RETINA cookie in your browser
RewriteCond %{HTTP_COOKIE} HTTP_IS_RETINA [NC]
RewriteCond %{REQUEST_FILENAME} !@2x
RewriteRule ^(.*)\.(gif|jpg|png)$ $1@2x.$2
# if @2x isn't available fulfill the original request
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)@2x\.(gif|jpg|png)$ $1.$2

# SEO URL Settings
RewriteBase /abantecart/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)\?*$ index.php?_route_=$1 [L,QSA]
  </IfModule>
</Directory>

Please note you need to restart Bitnami php to apply changes   

Hello.
The correct ink to admin is based on what is set during installation process of the AbanteCart.
yourdomainname.com/index.php?s=[your_admin]
 [your_admin] is provided by you during installation and can be located in system/config.php AFTER installation.
http://docs.abantecart.com/pages/tips/troubleshooting.html#admin