I have somehow managed to replace the default movie player, with my FTP client. I'm not sure how that happened, but now every time I double click a movie file in Finder, my FTP client launches. Can someone tell me how I can go about changing the default application that launches for certain file extensions?
Select a video file, press ⌘I, change the application under Open with, and select Change All.
You can also use duti to configure default applications in a text file.