I installed the mod to the server and the console is now constantly emerging errors and server lag.

Uh oh. Maybe I forgot an @optional somewhere. Would it be possible to post an excerpt from the server log?

http://pastebin.com/S5SUV4Mf

This entire log

That's weird. I'm not doing anything with entities that should cause them to get flagged as a lag source, and I can't seem to replicate the problem with just Red Controls. I noticed, though, that it says the world was previously used with some other mods that aren't installed anymore. Does the same thing happen in a fresh world? I guess it could be that the entity thing is a false alarm and the lag is something related to that?

This happens in pure world. I will try to set a different core.

I changed the core server in the recommended version of Forge. Nothing changed. Errors appear in the console as it was.

I just tested with forge 1.7.10-10.13.4.1558-1.7.10 (on both server and client) and I still can't seem to replicate the problem. Do you know if the problem still occurs without UltraminePlugin? That looks like it might be the main difference between our setups.

I used the same version of Forge. The problem remains.

I also updated java to 1.8.0_66 64bit, and still can't replicate the lag and log messages. This is getting frustrating. If I could get the problem to occur on my end, at least I could try profiling it or something to find out where the lag is coming from.

it was necessary to allocate more RAM