Haven't played for a few weeks. Didn't have this error before, so don't think it's a configuration issue. But it showed up today with no other addons enabled.

Message: Interface\AddOns\GreenWall\Config.lua:137: bad argument #1 to 'gsub' (string expected, got nil)
Time: Fri Sep 21 08:17:29 2018
Count: 1
Stack: Interface\AddOns\GreenWall\Config.lua:137: bad argument #1 to 'gsub' (string expected, got nil)
[C]: in function gsub' Interface\AddOns\GreenWall\Config.lua:137: in function substitute'
Interface\AddOns\GreenWall\Config.lua:218: in function load' Interface\AddOns\GreenWall\GreenWall.lua:463: in function GreenWall_OnEvent'
[string ":OnEvent"]:1: in function <[string ":OnEvent"]:1>

Locals: (*temporary) = nil
(*temporary) = "%$(%a)"
(*temporary) = defined @interface\AddOns\GreenWall\Config.lua:137
(*temporary) = "string expected, got nil"

Appears to be happening mainly when a guild member logs on or off. It was not fixed with the "system message pattern" fix in 1.9.8
Also get the error when people join or leave a raid group. Lua errors popping up during a world boss fight are so fun =P

Can you send a copy of your configuration to [email protected]?

Thanks!

Turned out to be a configuration problem. Someone mistyped something in the guild info.