Its working fine Thankq so much Anas_Ahmar, I have done Step 1 simply its working 
(“1- The .htaccess in example.com should NOT has the RewriteBase /invoices”)
Hi guys,
I just got Anas_Ahmar’s solution working. perfect thanks.
Open the HTACCESS file, and change:
RewriteBase /
to
RewriteBase /your-directory
I have similar error,
I have mod-rewrite enabled,
I am installing in sub-directory so i have edited the .htaccess in the subdirectory as mentioned above.
I get to the screen where it asks for database details, I fill in the details and when i press the button ( which is “try again” even if it is for first time i am setting up ) it leads to 500 server error.
I check the apache log files and it has this " “GET /invoices/setup/configure_database HTTP/1.1” 500 -"
any help would be appreciated
Look in your webserver error logs. There should be entries about this error in details.