Xampp SQL /php: when preview "websitename/index.php" web browser goes to localhost/index.php

This is a beginner question.

I started to build a practice website in xampp/htdocs folder. however, when I preview a page "index.php" of the website, the browser goes to "localhost/index.php" and it displays an error message:

"Warning

: require_once(Connections/connQnpTest.php) [

function.require-once]: failed to open stream:  No such file or directory in

C:\xampp\htdocs\index.php on line

1

Fatal error: require_once() [function.require]: Failed opening required  'Connections/connQnpTest.php' (include_path='.;\xampp\php\PEAR') in  C:\xampp\htdocs\index.php on line 1"

It will display the correct webpage if I manually type in "localhost/"practiceWebsiteName"/index.php .

any idea, please?