See below how you open a locked washing machine that has encountered an error.

EC HYDROS SW SERIES & EC HYDROS QW SERIES

XW SERIES & HW SERIES

EC SIDROS BW SERIES

FS SERIES

At the bottom of the front there is a panel you need to remove.

When the panel has been removed, you will see a string in the left corner. Pull the string and the door will open.  

CW SERIES & P SERIES