Lumbering Fool doesn't feel SpaceBar (PC)

[ZioNemo]

Hi,
I am badly stumped with the Lumbering Fool boss.
Problem is, after first sequence (r-click, spacebar+, r-click, l-click, l-click) and subsequent fall to lower floor I am unable to complete the second sequence which starts:
r-click, spacebar+, r-click, SPACEBAR

No matter how I hit spacebar the game acts as if I did nothing.
I am pretty sure I did the right thing at least once.

I installed on three machines (2 win7/64 and 1 Vista/32) and I'm stumped in exactly the same place.

Is there something I can do? (aside throwing away the game, of course)

Regards
ZioNemo