You can build one by using jsTree and JQuery datatable which are free and only require JQuery. They both can be configured to use ajax and can be themed by either using a JQueryUI theme or by providing your own css. I use that combination in one of my projects and am pretty pleased with the results. There is also CKFinder and the filemanager from TinyMCE which cost money but can be configured to work together with most server sided technologies. They also integrate with CKEditor/TinyMCE so you can supply document editing capabilities inside your file hosting website.
I don't really know the script mentioned above but after taking a quick look at its download site it seems to work with ftp servers which, in my opinion is not what you want your file-hosting service to work with. Big hosting plattforms like Google Drive use BigData Databases which are elastic so that you can add more servers to the database cluster on demand and thereby increase the overall storage. This is not at all the same as 'bundling' some ftp servers together. This approach does not provide very much flexibility or security. Take a look at http://hadoop.apache.org/
which can be used to work together with CKEditor. If you want to code the filestorage yourself there is http://cassandra.apache.org/
ontop of which I am currently building a file-storage service that is supposed to host many terrabytes of data.