Im using bulletproof FTP server, my FTP was working up until 5 minutes ago, when i try and make it go online i get the following message:

20/01/2004 21:42:19 SERVER: Unable to start server, port 21 may already be in use.

i tried changing the port to like... 22 and 23, and some others but since i know nothing about PC's really, that was just guess work, and it didnt work... anyone help?