I have been using Cyberduck for a long time on my computer at work, and I downloaded it on another computer that I use occasionally and it uninstalls itself after I use it. The icon turns into a question mark on my toolbar (I am attaching screenshot of this) and I can't open it, it doesn't appear in my Applications folder, its just gone. When I re-download and re-install it, all my bookmarks show up and it looks like nothing happened. I have re-installed it four times now, and I would like to stop doing this.

Is this a bug? Is there something I am doing wrong? I am not doing anything differently than I did when I downloaded it on my original computer, and it has been there for 2 years working perfectly...