[Correlli]

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
new cmd[256], idx;
cmd = strtok(cmdtext, idx);

if (strcmp(cmdtext, "/kill", true) == 0)
{
SetPlayerHealth(playerid, 0.0);
return 1;
}

return 0;
}

This will fix the warning. About the error, you're missing a bracket somewhere in the script probably.