Flashing Espruino fails, bootoader LED not pulsating

Thanks for letting me know... So just to be sure, this is pretty much what happens for you:

• The blue LED is pulsing on the Espruino board
  
• You click Write Firmware
  
• Web IDE says Downloading Firmware (very quickly)
  
• Web IDE says Initialised
  
• Web IDE says Erasing... And red/green/blue leds start winking
  
• Web IDE says Writing Flash... and the blue led on the board is still just pulsing blue
  
• Finally it says Error Flashingand the blue led on the board is still just pulsing blue