From the manual page 24:
'Door' is flashing in the display window...
?Shut the door firmly, until it clicks.
The symbol should now go out.
I suspect the door sensor has failed. It thinks you haven't closed the door, so it refuses to do anything at all. It's called a Door Interlock, it has a switch or sensor built into it.
First try unplugging the washer for 60 seconds and plugging back in to try to reset the controller. (Dry hands only!)
If the door interlock is a simple switch, you should be able to check it with an ohmmeter. I would check it first before buying a new one.
The part number is HPTC00085194 or C00085194, here are a couple places you can buy one. You can also find them on ebay.
Washing Machine Door Interlockby Indesit
Door Interlock Washing Machine
WASHING MACHINE DOOR INTERLOCK C00085194 design may vary