tekram .. the sql in the original moku sql patch in the fileset, is missing those extra table/field values, so your database will be missing them too.. I had to work out what extra was required in the sql, by comparing with the product music entries.....
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darkwander my authors search works ok,
this is an example partial url of the requested page when I click on a sidebox author,
you can check if its doing a similar querystring layout
Code:
... /index.php?book_authors_id=7&typefilter=book_authors&main_page=index
If thats ok, then the filter file in /includes/index_filters/book_authors_filter.php is not working for some reason..
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Also for something else, moku says about mods...
'one file have to be override to make this contribution possible.

It's the module file "product_listing.php":
includes/modules/my_template/product_listing.php
Wich overrides this core-file:
includes/modules/product_listing.php

If you want to modify your own file, just add a new Observer/Notifier around
line 123: (use a diff tool to see this single difference between both files)
$zco_notifier->notify('MY_NOTIFY_GOT_PRODUCT_LIST_NAME')'
I think the sample product_listing.php file moku supplies (now) has two minor problems, firstly there appears to be a code block repetion under the notifier line

secondly, the file he supplies is a 1.3.0/2 one, so for 1.3.5 get the actual includes/modules/product_listing.php file and insert the notifier line in that 1.3.5 one, as the code elsewhere in the file I thought had changed slightly from 1.3.2

Whether you re-insert product_listing.php say in
includes/modules/classic/ (if you use the classic template)
or
includes/modules/ to replace the actual one,
is up to you.

'my_template' is just the generic folder name, you need to rename that 'my_template' folder in the moku fileset with your current template name, or remember to copy it into the correct folder later.

Similarly the moku css file for the book template is in a my_template folder.