PDF indexer returns 404 error on found URL

I've purchased the PDF Indexer package to allow registered users of our website to search the newsletter PDFs. I've installed the component in version 5.4.2 of Joomla; configured the component; indexed the files and enabled the plug-in.
The search works as expected (first image) but the link to the file returns a 404 error (second image)
Is there an additional configuration value that I need to set?
 

Hi Dick,
Could you please submit ticket into category: Edocman and provide your site url and super admin account for checking the problem?
Thanks
Dam