[Jarnu]

Firstly.

Use sscanf (for better parameters and usage).

pawn Код:

CMD:osetcash(playerid,params[])
{
    new name[100], amount;
    if(sscanf(params,"s[100]d", name, amount)) return SendClientMessage(playerid, 0xFF0000FF,"Syntax: /osetcash [name][amount]");
    new string[128];
    format(string,sizeof(string),"Users/%s.ini",name);
    if(fexist(name))
    {
        new INI:File = INI_Open(string);
        INI_SetTag(File,"data");
        INI_WriteInt(File,"Cash", amount);
        INI_Close(File);
    }
    else { SendClientMessage(playerid,COLOR_YELLOW,"{FF0000}..::{FF6347}[Database]:Account not found{FF0000}::.."); }
    return 1;
}

Edit the above according to your need! thats just an example.