Matter resolved:smileyvery-happy:
I copied a link to the LS-firmware-updater on the desktop. On rightclicking and opening properties, I inserted /force at the end of the target string. This did it.
I then established the hacks that enable the LS to run Twonky Mediaserver (quite an ordeal for someone who doesn't speak UNIX). Necessary tools: acp commander, puttytel, addons.tar, hacking of smb.sh/smb.conf/rcS, twonky mediaserver (I used version 4.4.6). There are some very useful wikis around that can be followed.
But thanks for your advice to contact the local dealer (who in my case is some 4000 miles from my house as I live in Yemen).