Multicraft Tekkit install: Invalid jar

[VisibilityOfficial]

Title: Multicraft Tekkit install: Invalid jar

Version: 3.1.2

OS: Win 7

Java Version: 7

Description of Problem:

I have installed Tekkit.jar in the list but when I start the server it says it is an invalid jar. I have tried renaming it... (Installing to the Daemon jar directory)

Error Messages:

[server] INFO Error: Invalid or corrupt jarfile

Error Log:

08.01 20:55:45 [Multicraft] Server stopped

08.01 20:55:45 [Multicraft] Looks like a crash, check the server console. Return value: 1

08.01 20:55:45 [Multicraft] Server shut down

08.01 20:55:44 [server] INFO Error: Invalid or corrupt jarfile C:\Users\Hayden\Desktop\Desktop\Multicraft\multicraft\jar\craftbukkit.jar

08.01 20:55:44 [Multicraft] Loaded config for "Tekkit-3.1.2"

08.01 20:55:44 [Multicraft] Starting server!

08.01 20:55:44 [Multicraft] Loading server properties

08.01 20:55:44 [Multicraft] Server stopped

08.01 20:55:44 [Multicraft] Retrying server startup