Failed compiling 'EventManager.cs':
Failed compiling 'EventManager.cs':
Couldn't find required plugin 'EMInterface' for 'EventManager'
Couldn't find required plugin 'EMInterface' for 'EventManager'
Failed compiling 'EMInterface.cs':
Failed compiling 'EMInterface.cs':
1. The type or namespace name 'EventManager' could not be found (are you missing a using directive or an assembly reference?) [CS0246]
(EMInterface 64 line 808)
1. The type or namespace name 'EventManager' could not be found (are you missing a using directive or an assembly reference?) [CS0246]
(EMInterface 64 line 808)
2. The name 'EventManager' does not exist in the current context [CS0103]
(EMInterface 93 line 73)
2. The name 'EventManager' does not exist in the current context [CS0103]
(EMInterface 93 line 73)
Warning! 'EventManager' uses UnityEngine.GameObject.FindObjectsOfType. That may cause significant performance drops, and/or server stalls. Report to the developer or use at your own discretion!
Warning! 'EventManager' uses UnityEngine.GameObject.FindObjectsOfType. That may cause significant performance drops, and/or server stalls. Report to the developer or use at your own discretion!
Failed compiling 'EventManager.cs':
Failed compiling 'EventManager.cs':
Couldn't find required plugin 'EMInterface' for 'EventManager'
Couldn't find required plugin 'EMInterface' for 'EventManager'
how do i fix this?

Check the EMinterface is actually loaded on your server, 
Type plugins in rcon console and it should show all the plugins that are loaded.