Crash log here: http://pastebin.com/ipKANPw2 I will check if I am assigning too much/little RAM to help others with this error, otherwise I have no idea.
Having quickly checked the log, it seems that the issue is with extracting files. I'm assuming that it's probably gonna be a "You're on a Mac HA" type answer to that, so what should I do? (Not enough RAM for SKCraft in a linux/windows VM and given up with dual-booting)
That fixed it thanks. BTW, I then kept on crashing after ~1 minute of being on the server. This was fixed by setting my min RAM to 512, and max to 768, with the perm gen being 256. I can now run with ~20 FPS constantly on lowest graphics with no crashing. On two clients at the same time.