Problem opening some PDF files in Adobe Reader X & XI

This often happens if people save files from Safari, on the Mac, the wrong way. It's a sad but true fact that several ways to save PDF files from Safari seem to work but actually save some old junk instead of what you actually want.

The only safe way to do it is to hover over the PDF until Adobe Reader's toolbar appears, and then to click the Save icon.

SumitV, the link does not really help for non-tech users like me.  What is HKLM, where do I find it, what might I see when I get there, what would happen if I make a mistake in there?  All these need to be explained by Adobe (and others who try to help) than just dropping a link and saying "Go figure this on your own."  If Steefan can do that he wouldn't be on this forum.  Please explain in a clearer form what the incompetent Adobe tech support is trying to say in that link that you've posted.  That would be really helpful.

Thanks,

HS