Thanks for continuing to help. Some additional info....I have just upgraded to version 5 of FoxIt Reader - which I use to open PDF files rather than Adobe Reader. One of its options is to "Display PDF in Browser" - with this unchecked, the EFB throws the security error. But with it checked, I no longer get the security error, and the EFB appears to open the PDF but it does not display. Instead, I get a tiny icon in the top left corner of the browser and right clicking does not offer any relevant options. Hopefully I have managed to attach a JPEG screenprint to show you what I am talking about....In terms of your specific questions:
Can you read other documents (HTML, TXT, etc) from the Display Unit Library? YES
I assume you've copied the tutorial from your FSX folders into your \Documents\AivlaSoft\EFB\UserData\Library\ area, correct? YES
Can you read other PDFs that are in your \Documents\AivlaSoft\EFB\UserData\Library\ folders using the Display Unit Library? NO - I HAVE MOVED ALL SORTS OF PDF FILES AND THE OUTCOME IS THE SAME (SMALL ICON IN TOP LEFT CORNER)
If you answered yes to that, can you read other PDFs that are in the same folder as your iFly tutorial using the Display Unit Library? SEE ABOVE
If you answered yes to that, could you try making a copy of the tutorial (in Explorer) in the same folder and making sure the Access Control List is very liberal? (Add "Everyone - Read" to the Security tab under the file's Properties.) I CAN OPEN THE TUTORIAL.PDF IN INTERNET EXPLORE OR FIREFOX AND IT WILL OPEN IN A POP-UP FOXIT WINDOW
Thanks for your ongoing support
Chris