cant connect / error flashing

Hello,

I was really happy to receive my Espruino today :) , so I quickly wanted to try playing with it. However, despite of my efforts, it seems it is not working ... so frustrating ! Here is the detail of what I tried.

• using an old iMac, still using Snow Leopard.
  
• connecting the Espruino through the USB cable coming from my Sony phone, so cable is working properly (using it regularly for charging / USB Mass Storage and so on). When connecting, the blue + red leds both blink quickly once.
  
• Mac OS X popups a dialog box, indicating new network interface was detected, "STM32 Virtual COM Port". Is it logical ? It asks to setup it (networking, as a modem setup ...), or Cancel. What to do here ? If I want to setup, it offers modem like settings (phone number, and so on, tried various ones without any success).
  
• then I tried in console:
  ls /dev/tty.*
  /dev/tty.usbmodem5d11
  
• in Arduino Web IDE, I also see a corresponding entry, cu.usbmobem5d11 (?), but I selected the TTY one anyway.
  
• clicking Connect displays "Connected", but pushing code to the device seems to not execute anything. Also, I did not get any message about firmware update ?
  
• tried again with screen in console, no result / no prompt / nothing.
  
• Finally I tried to flash. Rev 1.3b, so I had to manually select:
  http://www.espruino.com/binaries/espruin­o_1v48_espruino_1r3.bin
  (is it the correct one ? no 1r3b ?)
  
• pushing buttons worked properly, the blue led is slowly moving. Web IDE displays "Initalizing", then almost directly "Error Flashing.".
  So I really suppose something needs to be setup first ? (probably around STM32 Virtual COM Port, but how to do it ?).