It's user specific so it depends on your wippiespace name and the server you're on. Easiest way is to setup the HTACCESS & HTPASSWD files thru My Wippies (
My Wippies ->
Webspace administration ->
Directory administration -> Choose a folder and check
Password protected on
Access management section). It creates the necessary files automatically and all you have to know/define is the username and password.
If you have PHP support ordered for your wippiespace, you can also check the absolute path with this PHP file (name it as you like, upload to the server and access it thru your browser):
<?php
echo realpath(__FILE__);
?>