SOLVED....

What was that about lost Kingdoms and horseshoe nails... sometimes it is the most obvious that eludes us.

The author of this document created the Hyperlinks using the "Existing File or Web Page" option instead of "Place in This Document" option. And I did not notice that.

Therefore when Adobe Reader tried to redirect control to the Hyperlink it needed to "link to a file" which the security settings on that machine would not allow.

So in closing this Thread.... thank you to Jim and Paul for your help and the lesson I have learned from this is - "first look for the obvious before assuming something more complex is going on".

T.