Code:
#define L4D_MAXCLIENTS_PLUS1 (MaxClients+1)
MaxClients doesn't work this way... essentially you're trying to define a compile-time definition using a runtime variable.
Incidentally, this is always why global arrays have to be defined in terms of MAXPLAYERS instead of MaxClients.
I would heavily suggest just using MaxClients+1 wherever you current use this define.
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