Well, its because the message that was sent to the cmd user (Admin) wasn't formatted. You only formatted the message that was sent to the target player. Also, i saw that you have fetched target player's name but didn't utilize it at all.
PHP код:
CMD:givescore(playerid, params[])
{
if(!IsPlayerAdmin(playerid))
return SendClientMessage(playerid, COLOR_ERROR, "[ERROR]: You are not an admin!");
new targetid, score;
if(sscanf(params, "ud", targetid, score))
return SendClientMessage(playerid, COLOR_ERROR, "[ERROR]: Usage /givescore [playerid] [amount]");
if(targetid == INVALID_PLAYER_ID)
return SendClientMessage(playerid, COLOR_ERROR, "[ERROR]: Player is not connected.");
new str[75], pname[MAX_PLAYER_NAME];
GetPlayerName(targetid, pname, MAX_PLAYER_NAME);
SetPlayerScore(targetid, GetPlayerScore(targetid) + score);
format(str, sizeof(str), "Admin has given you %d score.", score);
SendClientMessage(targetid, COLOR_PURPLE, str);
format(str, sizeof(str), "you have given %d score to %s(%d)", score, pname, targetid);
SendClientMessage(playerid, COLOR_YELLOW, str);
return 1;
}