Bouchart: Try manually copying the contents of all three CDs into a folder and starting up the program with DosBox. I'm guessing that the game runs in DOS mode, which Windows 7 or 10 won't natively recognize.
Yeah the game plays in DOS! Yes I thought I had to copy all the 3 cd's content into the same folder, but I was always confused with the first folder of all 3 cd's named ITOON, it should contain the same files so I wouldn't worry about overwriting: they have the same name, but I think they're also the same files: that was the reason I hadn't already copied the 3 cd's content into the same folder.
Each cd contains 3 folders: one of them is always ITOON: so I left just one of them, and copied the other two folders of CD 2 (TOON1 and TOON2) and the other two folders of CD 3 (TOON4 and TOON5) (I don't know why TOON3 doesn't exist).
And now IT WORKS!!!!! :)
It's kinda pixeled but, it's just magical to play this game again after a long time, I was 12 years old when it came out, and played all through the nights of that far 1996 or 1997. It's like to live again my childhood.
THANK YOU to you all!!! You were so kind, and this is a faboulous community: it's such a shame that DOWN IN THE DUMPS isn't downloadable here in GOG. I bought here POD, which plays great! and Feeble Files, other gems of my childhood. Thank you!! God bless you!!
Maxvorstadt: Have you tried to insert disc 2 into your disc drive when the message appears?
I tried but it does nothing :) I will cherish and hold the physical version as a beloved token!
COORECTION: TOON3 exists!! It's in CD1! I copied also all the content of CD1 exept for the files with the same names.