No, there is no way how to disable FTP. PSPad from 4.5.4 version suports SSL/TSL FTP transfer. It in't enough for you?
If you want to disable FTP transfers in your environment, disable FTP ports on server -- <http://forum.pspad.com/read.php?2,48890,48894> PSPad freeware editor http://www.pspad.com
