Running Minecraft Server 1.7.2 on Windows 8.1 in only possible by disabling Avast internet Security 2014.9.0.2006. Disabling antivirus is a bad fix.
Starting Minecraft Server resulting in nothing happening with Avast enabled.
I have exactly the same issue, but instead to cut of FireWall (that is suffisent), I have unistalled Version 9 and reinstalled version 8. I think is better for security.
I am awaiting from avast instructions to authorise Minecraft Serveur 1.7.2 to be fully excuted under Avast 9
Best Regards
JNJOLLY