[Konstantinos]

It should be:

pawn Code:

if (sscanf(params, "rs[128]", giveplayerid, text)) return SendClientMessage(playerid, COLOR_GRAD2, "Usage: /report [id] [reason]");
// Specifier "s" needs the size and it becomes: "s[size_here]".

And this function has 3 parameters and you have only 2 here. Change to:

pawn Code:

if( giveplayerid != INVALID_PLAYER_ID ) SendReportToQue(playerid, giveplayerid, text);