I've just uploaded a new build of fTelnet. This one includes a couple fixes identified by users, and implements batch downloading. The method for starting a transfer has also changed, rather than the CTRL+ALT+U and CTRL+ALT+D that previous versions used, there's now options on the right-click context-menu. After files are downloaded, options to save them will also be added to this context-menu.
If no big errors exist, I hope to put together a release package in the next day or two so it'll be easier to implement fTelnet on your own site.