Appears that you don't have updated all modules with amxx1.8.2 package.
Also, disable all 3rd party plugins, and enable them 1 by 1 untill you get the error so you can know which plugin has the error.
You may even run the server without metamod for a while to make sure the problem is not already there.
Read this :
https://forums.alliedmods.net/showthread.php?t=224451