This feature will not work on a reseller account. You will need a dedicated server or VPS plan and have Fantastico installed to have this tool.
Fantastico is available on VPS with cPanel and Linux Dedicated Servers for $4 per month (installation included) and can be ordered by contacting our billing support at billing@hostgator.com.
cPanel is a popular web hosting control panel that helps you manage your hosting account and assists you in creating web sites, managing e-mail addresses, & installing applications to a server.