Testlink application was properly configured in my localhost through XAMPP, not until I changed my antivirus to ESET NOD32 Antivirus 4.0.314. After successful installation of the free antivirus, I can no longer access applications on my local, from the previous working URL:
I was directed to http://www.localhost.com:8081/testlink/login.php, with an error message of
The connection to the server was reset while the page was loading.
The network link was interrupted while negotiating a connection. Please try again.
After uninstalling NOD32, everything works back to normal.