I've been playing Roguelike Adventures and Dungeons 2 with a friend, and recently added Mob Grinding Utils to the pack in order to build a mob farm, but I discovered that the Mob Masher wasn't able to deal any damage to mobs. My first thought was that the mod that adds an RPG-style leveling system and level requirements to use equipment was preventing the masher's fake player from using the imaginary-not-really-there-sword, and I was able to change that mods config to set the sword's skill requirement to 1, but that didn't fix the problem. Any assistance would be great.

For posterity, you have to turn on the mob masher with a redstone signal.

You solved the problem? because a am in the same modpack and added the Mob Grinding Utils and the Mob Masher don't work.

Does this pack have ftb utilities, or any other mod that protects areas? those can generally interfere with it.

A possibility is ftb utilities chunk claiming, try allying with the fake player for mgu.

I would check if this is the issue by unclaiming the chunks the masher is in, and seeing if it starts working, if that fixes it, you could try inviting the mob grinding utils fake player to your team.

Does this pack have ftb utilities, or any other mod that protects areas? those can generally interfere with it.

I just checked the pack, it doesnt have FTB chunks or ftb utilities. It does however have following ftb mods:
FTB Backups (Forge)
FTB Library (Forge)
FTB Money (Forge)
FTB Quests (Forge)
FTB Teams (Forge
FTB Ultimine (Forge)