"The pdf.js library could not be found." (PDF module) I installed pdf.js with the PDF module in an effort to show pdf on the fly on my Drupal 7 site. I keep Drupal 7 constantly upgraded on Ubuntu on an instance an AWS. 

I installed the module using drush which placed the module at sites/all/modules/pdf. I then copied pdf.js to: sites/all/libraries.

After installing I have created a new content type called PDF and I added a file field that is able to only include a pdf file. 

I selected the display to show: "PDF: Default viewer of PDF.js". I then added a content with a PDF file in it selected and uploaded. 

While trying to show it I get the message: The pdf.js library could not be found. And down the page: pdf: Please download and install pdf.js! 

Can anyone help?
Where do I put the JS file?
Is there a problem with the FDF module?
The path will be like this /sites/all/libraries/pdf.js.

pdf.js is a FOLDER not a FILE. It is very strange to have a folder with a DOT in the name.

I have attached a screenshot on the folder hierarchy that works.

SUMMARY:

The folder in your libraries folder must be named: pdf.js, you will have to rename the top folder of anything you download to pdf.js (in this instance pdf.js is not a FILE, but the container of the library)
See screenshot for the correct file hierarchy.