Like I said, I had the same problem.
The server launched perfectly (or appeared to, anyway), and I could connect from the desktop computer that it was running on, but no other computer could connect. The vanilla bukkit server still worked and 25565 was open. People could connect to Tekkit when I ran the same server files on my laptop, but not my desktop. When I launched the server with a different .bat, however, the server became visible and people could connect to my desktop.
Same exact problem word for word.