G4DG37

I just updated to the Tekkit server 1.2.7b... But it was doing this with 1.2.7 as well

every time i try to do the /help command, I get an unknown error has occured... here's a screenshot for anyone who cares

I have been looking everywhere and I cannot find a thing about installing a new Tekkit Server 1.2.5(and no not Tekkit Classic... I'm really tired of seeing that every time I google it)... I know there's a way, but the last time I ran a server was back in the beginning of Tekkit Lite, so I'm no where near an expert. I really need to install a Tekkit Server with Tekkit 1.2.5(for Minecraft 1.6.4) and I would appreciate any help. Thanks in advance.