There is no single file extension. Some may be a web site ending in ".com" or ".gov" or may be a lengthy web site address like: http://geneteka.genealodzy.pl/index.php?op=se
I understand that these links should not open MS Word, but they do, even though the file associations are not for MS Word.
I have installed two different versions of Adobe Reader without success in causing the links to open in the browsers rather than in MS Word.
I have removed and reinstalled browsers with no success. I have changed the default browser to Chrome, FireFox and MSIE without success in causing the links to open in the browsers rather than MS Word.
I suspect that this is a setting in Adobe Reader that I have yet to find.
I take the same document to other computers and it works as expected, opening the default browser and then opening the web page.
I am stumped.
Sorry, I think I was wrong in my earlier post; it should be the http: protocol that would open the browser.
Can you try the following: Start | Run, then paste some URL like your http://geneteka.genealodzy.pl/index.php?op=se and hit Enter. Does that open in the browser, or in Word?