it is because your server php version need to be at least 5.4 for this add-on ( only for advanced search feature ), but if you don’t need that feature you can disable the code using return 0; after function name or give me temporary wp-admin login info, I can do that for you.
You need to create a custom link template, docs for templates are here http://www.wpdownloadmanager.com/doc/templates/ , FYI: while creating link template you simply need to skip [page_link] tag to avoid link to details page.
Yes, you can use your own custom html/css with link template.
“Fatal error: Call to undefined method WPDM_CategoryHandle…” the error only may happen if all files not uploaded properly, please delete current installation and reupload latest version.
wpdm-categories short-code will show only categories, not the packages. For showing package under categories, you need to use category short-code. I added some sample in that page, please check http://vocaloid.de/downloads/ .
In fact, the query they mentioned is a simple wp query with a search phrase, nothing to optimize there at all. But please update download manager asap, we have fixed some security issue there.
