Valve has so far never updated anything on l4d2. So it has to work perfectly.

These are the reasons:

• Make sure you have the file "admins.txt" with your Steam ID number. Located here: C:\Program Files (x86)\Steam\steamapps\common\Left 4 Dead 2\left4dead2\ems\admin system
  
• Do not have any mod in conflict with the admin system.
  
• Always have the command "sv_consistency 0" so that people are not kicked on your local server with mods.
  
• Make sure you don't have any bad working scripts or vscripts. That causes the mod to stop working.

Let me know if something doesn't work for you. If you've been testing versus mode. Just go to the file "addonconfig" and set the values to 0. Located here: C:\Program Files (x86)\Steam\steamapps\common\Left 4 Dead 2\left4dead2\cfg

I checked the admin txt and its there with my steam id (works fine with just me) so thats not it.
I will add sv_consistency 0 to autoexec.cfg and try.

The admin scripts has always shown in red even by itself and collides with the core .vpk vscripts which i doubt i can just gut from the game


File scripts/vscripts/admin_system/vslib/easylogic.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/admin_system/vslib/entity.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/admin_system/vslib/fileio.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/admin_system/vslib/hud.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/admin_system/vslib/player.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/admin_system/vslib/randomitemspawner.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/admin_system/vslib/responserules.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/admin_system/vslib/timer.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/admin_system/vslib/utils.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/coop.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/director_base.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/realism.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/scavenge.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/scriptedmode.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/survival.nut collides in VPKs:
Admin System
Admin System 2.0
File scripts/vscripts/versus.nut collides in VPKs:
Admin System

+100 more lines

Those seems normal. You are simply configuring and loading the mod on your server.

But out there avoid not using another mod that contains vscripts that conflicts with the mod. For example using custom weapons from rectus.

Ran local sever with only admin and admin 2.0 with sv_consistency 0 in auto exec (confirmed this with command sv_consistency in console and it reports back sv_consistency 0 def 1 ) still in red on add-on list with conflict error message.

If the Admin System and Admin Menu are in conflict with another mod. Just disable the mod that hurts those mods.

"Ran local sever with only admin and admin 2.0 with sv_consistency 0 in auto exe"