[Dayrion]

You can do it easilier.
Let's take a example with explications.

PHP код:

if(sscanf(params,"us[25]", target, nName)) return SendClientMessage(playerid, -1, "/name [id_joueur] [new_name]"); 


Then do some verefications like

PHP код:

if(!IsPlayerConnected(target)) return SendClientMessage(playerid, -1, "This player is not connected.");
format(PATHT, 50, "/Players/%s.ini", nName);
if(fexist(PATHT)) return SendClientMessage(playerid, -1, "Name already taken"); 


Remove the old file and attribute the new name.

PHP код:

        fremove(UserPath(target));
        SetPlayerName(target, nName); 


Put new parameters like a new player who is regestering on your server.

PHP код:

new INI:File = INI_Open(UserPath(target));
        INI_WriteInt(File,"MDP", PlayerInfo[target][pMDP]);
        INI_WriteInt(File,"Admin", PlayerInfo[target][pAdminlvl]);
        INI_WriteInt(File,"Cash", PlayerInfo[target][pCash]);
        INI_WriteInt(File,"Score", PlayerInfo[target][pScore]);
        INI_Close(File); 


Dont copy/paste this code. He comes from my gamemode (my /name commands) and may not work on yours because I didn't put the whole code.