I've got a computer that Cyberduck locks up on when you're trying to upload a file to an FTP server. You can get to the file browse window and select your file, but past that the program locks and has to be killed via the Task Manager. For what it's worth, it also locks up if you try to open the Transfers window.
I've attached the log from the program to this ticket. The machine is question is running Windows 7 Pro, x64, SP1. I tried to copy the transcript from the Log Drawer, but I couldn't even get it to open.