Server Suddenly Crashed Crashed and won't start

[Nitro Nito]

Firstly, I'm sorry if this is in the wrong section :X

I play on this tekkit lite server my friend owns and it suddenly crashed out of no where, and wouldn't start back up. I copied over the save and tried to play it on single player, and it would just get to "building terrain" and freeze there. I was the only one on the server at the time, and I wasn't doing anything crazy, just running. After reverting to a back up, and a certain amount of time passed, the same thing happened again. I have no idea why it keeps happening, and I'm pretty new to Minecraft, let alone Tekkit, so I don't know what to do.

In addition to Tekkit Lite, the server also has Jammy's Furniture mod and the Portal Gun mod, but all the ID's were changed so no mods conflict with one another. I don't see why the mods would be a problem though because we've been playing so long and haven't changed/added any mods or changed tekkit/forge/etc. in anyway. Could it be a problem with Minecraft itself, and not Tekkit Lite?

If there's any information I can provide that would help you guys in helping me, tell me