Hopefully final update: I just had to restart the download a few times and the necromancy mod worked. But, when everything was done downloading, it went to the Mojang screen and froze for about a minute. Any advice or suggestions?
I downloaded the launcher, I have the latest version of Java, and I tried to download AotBT, but it said Failed to download. It was apparently caused by the Not Enough Keys mod. Does anyone have any advice?