[iZN]

Код:

C:\Users\Areeb\Desktop\Server\gamemodes\Groove.pwn(380) : warning 235: public function lacks forward declaration (symbol "OnPlayerPrivmsg")
C:\Users\Areeb\Desktop\Server\gamemodes\Groove.pwn(395) : warning 235: public function lacks forward declaration (symbol "OnPlayerInfoChange")

The error you've mentioned. These callbacks are NO longer available. Just remove them from the script.
Also the language is PAWN, not PAWNO. PAWNO is just an IDE to edit .pwn extension.