That question is already solved!
So I ended up with a Cubase.sit file in the Macintosh Classic hard drive.
Now, if I unstuff it within the mac, then this
http://personales.ya.com/juanjavier_xxx/cubase_sit_unstuffed_on_mac.JPG
is what I get. A folder called Cubase, which contains just a Cubase2.5.1r3.img, two folders called Roland and Midi Manager and a file called «sans titre».
However if I expand the cubase.sit file within window$, I get an .img file which, if I transfer to a mac formatted floppy yields this
http://personales.ya.com/juanjavier_xxx/cubase_icons.JPG
...which is the former .img file, but expanded.
However, note that as I told before, if I double-click in the Cubase 2.5 executable icon, this
http://personales.ya.com/juanjavier_xxx/cubase_error.JPG
appears. So, what should I do next?
I suppose that I should mount the Cubase2.5.1r3.img file but, how is that done?