In my previous blog I have installed Nominatim in my home folder and changed the directory of local server from /var/www/html to /home/amisha.
To do the same you can refer my blog -> reference
That was creating lot of problem to me as I was not able to run any php file in /var/www/html directory. So, first of all I restore the local server to the default directory.
But I was not able to run the Nominatim located in the /var/www/html directory.
After reading the settings.php file I came to know that
It was searching to the localhost/search.php but the actual path was localhost/Nominatim/build/website/search.php
Finally, the problem is solved.