Lua error in Module:Effective_protection_level at line 64: attempt to index field 'ext' (a nil value).

Backtrace:

(tail call): ?
Module:Effective_protection_level:64: in function "effectiveProtectionLevel"
Module:Protection_banner:121: in function "new"
Module:Protection_banner:838: ?
(tail call): ?
mw.lua:527: ?
(tail call): ?
[C]: in function "xpcall"
MWServer.lua:99: in function "handleCall"
MWServer.lua:313: in function "dispatch"
MWServer.lua:52: in function "execute"
mw_main.lua:7: in main chunk
[C]: ?