I was having an issue with the newer versions of Forge Essentials crashing with:
java.lang.RuntimeException: java.lang.ClassNotFoundException: cpw.mods.fml.common.asm.FMLSanityChecker

After testing it on a clean server and re-adding mods one-by-one, this problem only occurs when Mariculture is present. Each mod loads just fine without the other one. I wanted to reach out here and see if maybe you had an idea of what the issue might be.

Here is my log for the error:
http://pastebin.com/Bkne2FBf

And here is the issue report on the Forge Essentials github:
ForgeEssentials/ForgeEssentials#1333

Thanks for your time!

For the record, FE is using transformers supplied by the Mixin project, which will also be used by the Sponge API in the future.

To save a bit of time, this line - VanillaOverride:108 probably has something to do with it.

Considering it's been like that since my first 1.7 updates and it's had no issues with any other mods. I've got no clue what I'm supposed to do here. (Although it could be rewritten better).

@joshiejack fixed in Forge 1399. Go close it.

Looking at the code I have to agree, that is not really written nicely...
We would appreciate it, if you could take a look at the patching process and see where this problem comes from.
We will try to find the root of the problem, too.