Проблемы с кодировкой при переключении из Debug в Release в MSVS 2010

int _send(int infmainsocket, char file_name[])
           SOCKET main_ftp_socket=(SOCKET)infmainsocket;
    FILE * f;
    
    char send_buff[255];
    memset(send_buff,0,sizeof(send_buff));
 
    strcpy(send_buff,"PASV\r\n");
    if(send(main_ftp_socket,send_buff,strlen(send_buff),0)==SOCKET_ERROR)
        return 0;
    
 
    if(recv(main_ftp_socket,send_buff,sizeof(send_buff),0)==SOCKET_ERROR)
        return 0;
    
    
    if(send_buff[0]!='2')
        return 0;
 
    if( (f=fopen(file_name,"rb"))==NULL )
        return 0;
    
    SOCKET transfer_ftp_socket;
    if((transfer_ftp_socket=socket(AF_INET,SOCK_STREAM,0))==INVALID_SOCKET)
        return 0;
    sockaddr_in ftp_addr;
    ftp_addr.sin_family=AF_INET;
    ftp_addr.sin_port=htons(extractPortRFC959(send_buff));
    ftp_addr.sin_addr.s_addr=inet_addr(extractIpRFC959(send_buff));
 
    if(connect(transfer_ftp_socket,(sockaddr*)&ftp_addr,sizeof(ftp_addr))==SOCKET_ERROR) 
        if(connect(transfer_ftp_socket,(sockaddr*)&ftp_addr,sizeof(ftp_addr))==SOCKET_ERROR) 
            return 0;
        
 
    strcpy(send_buff,"TYPE I\r\n");
    if(send(main_ftp_socket,send_buff,strlen(send_buff),0)==SOCKET_ERROR)
        return 0;
    
    
    if(recv(main_ftp_socket,send_buff,sizeof(send_buff),0)==SOCKET_ERROR)
        return 0;
    
    strcat(strcpy(send_buff,"STOR "),strcat(extract_file_name(file_name),"\r\n"));
    
    if(send(main_ftp_socket,send_buff,strlen(send_buff),0)==SOCKET_ERROR)
        return 0;
    //printf("%s\n",send_buff);
    if(recv(main_ftp_socket,send_buff,sizeof(send_buff),0)==SOCKET_ERROR)
        return 0;
    //printf("%s\n",send_buff);
    
 
    int size;
    do
    {
        size=fread(send_buff,1,255,f);
        if(send(transfer_ftp_socket,send_buff,sizeof(send_buff),0)==SOCKET_ERROR)
            return 0;
    }while(size==255);
 
    closesocket(transfer_ftp_socket);
    fclose(f);
    if(recv(main_ftp_socket,send_buff,sizeof(send_buff),0)==SOCKET_ERROR)
        return 0;
    //printf("%s\n",send_buff);
    return 1;
}

for (i = strlen(dir); dir[i-1]!='\\' && i>0 ; i--);

char * extract_file_name(char dir[])
{
    char file_name[255];
    int i = 0 ;
    int j = 0 ;
    for (i = strlen(dir); dir[i-1]!='\\' && i>0 ; i--);
 
    for (i ; i < strlen(dir)+1; i++,j++) 
        file_name[j]=dir[i];
 
    return file_name;
}

for (i ; i < strlen(dir)+1; i++,j++) 
file_name[j]=dir[i];