My Cubase crashes each time I want to drag and drop a loop (with MIDI icon, so by pressing "map" on Ethno interface). It works sometime, but never more than twice

I've tried on Cubase SX3 (from a friend of mine), and it's the same with my Cubase Studio 4 (last update) on PC.
Does anybody has an idea ?
Thanks in advance to helping me

Arnaud.