I was also having this issue today 27/12/2014 when setting up a new server on Windows 7. It was a fresh install of Windows 7, Java 8 was my issue. I uninstalled Java 8 and Java 8 (64), then downloaded Java 7 and Java 7 (64) from the website installed both of them. Re launched my Tekkit and it worked fine.
Good luck, hope this fixes your issue too.