Wow there is everything and a little bit more :)
Can't make it work yet thou. I dosen't understand the zencart language yet.
A new freshly (3:rd to day) installed zencart and every thing seems fine. The zc_install folder deleted and admin folder changed to admin1 (just testing yet).
Now the tricky part starts.
The installation text for the V4 Book Mulitilanguage Product Type for V1.3.8 says
"Upload the main book files files in \catalogue to your zencart."
I assume that means /zencart.mydomain.se/public_html/catalogue and not manually putting the files in the different folders... or?
When I installed zencart I changed the admin folder to admin1 and in the configure.php also but that change dosen't inflict with V4 Book M... ADMIN_PATCH_SQL_EXTENDED_BOOK_TYPE_V4.txt file in any way... or?
The problem is when I am trying to add a product and choosing product_book it can't find the file in the admin folder... but I was forced to change the name admin to admin1... so obvious I have done something wrong, major wrong.