Cannot Install New Application with Fantastico

From OCS Support Wiki

[edit] Introduction

You will experience an error if you try to install a new application with Fantastico if you uninstalled the old application without doing so through Fantastico.

It is recommended to let Fantastico handle uninstallation of scripts that you installed with Fantastico instead of deleting them manually.

[edit] Resolution

To fix this problem, you will need to remove the file .fantasticodata/installed_in_root.php from your account. You may have to enable hidden files or folders in your FTP client to do this. You can also use cPanel's file manager.