When i start my FTB server, it immediatly shuts down and leaving no crash report behind. All this happened after i changed the ip adress inside the server config file.
Usually I find those that close straight away don't have java installed, but since you had it running prior to that, I'd suggest your server.properties file may contain an invalid character.
When you edit any server config file don't use the likes of wordpad or notepad, use a raw text editor like notepad++ or if you're happy use a hex editor with a plain text edit function.