I get this crash when I place universal cables: http://pastebin.com/F3S87Rv5
I have the exact same problem. Good thing the server isn't up yet. That said, I need to MC Edit the wire before I can relog. I would paste my file, but with the exception of the flags, the OS, and the java version (1.7 causes issues on OSX), the files are pretty much identical.
I have this aswell
Delete "mekanism" folder in GalactiCraft jar
will this result in something bad with galacticraft ?
It would seem that it is using an old version of the API. I deleted the mekanism folder as suggested, then replaced it with the current version of the API and it also fixed the problem, hopefully without losing integration.