Same problem here.
I tried what you advised, Sincronista, and it's still not working. The second plugin (personal) refuses to get activated once installed.
I must say the FTP way a little complicated: the 2 plugins instead of one, than when you unzip, you find again zip files inside that, then within the folder wunderslider-personal, the folder (plugin?) is called simply wunderslider (without "personal")... Difficult to be sure what to upload to the http://FTP...
In brief, I'm fed up. I'll wait that you update your plugin so that it can be installed through WP, like all plugins...