After the update the plugin has stopped working. I get this error when the plugin loads. 
"Error while compiling: BuildingGrades.cs(28,61): error CS0246: The type or namespace name 'MeshColliderBatch' could not be found. Are you missing an assembly reference?"
What can i do to fix this?

Sounds like you are using a VERY old update, as that error was from 4 months ago.

I did that update 4 months ago it just randomly stopped working again today. Just re took it out, put it back in and did a server restart. It now works but I cant figure out why it didnt work the first 3 times I did that.

Only way it would have not worked is if an older version was used somehow because if the code doesn't exist in the current, it wouldn't error.