I have some fresh installs today but it is gave me an issue:
The server was not able to find the document (./cgi/addon_softaculous.php) you requested.
Please check the url and try again.
I guess what should happen is that the install happens and redirects you to addon_softaculous.cgi but this fails.
If you reload the main plugin page it then links to the .cgi
And seems to work ok afterwards
Sir after unzipping the files Softaculous uses the addon_softaculous.php to complete the installation and once the installation is completed the addon_softaculous.php is deleted and the addon_softaculous.cgi file is used by Softaculous after installation. And the links in the WHM are not refreshed hence you will have to refresh the page once after the installation is complete. This will happen only once after the fresh install.