Trouble opening pdf's in x4

HI all!  Smile


I like my coreldraw x4.  This sign shop actually has a copy of x5 but it was so so so so awful that we had to take it off of the computer.

I am having more and more problems opening pdf's.  I end up with a rectangle with a line across the corner.  I'm assuming the people sending have newer adobe than what x4 can handle?  I can open the pdf;s in adobe reader but only give option to save as pdf.  I just looked and it says PDF VISTA .  Is there a way to save them as an older one?  Kind of how corel draw can be saved as an older version? 

And for some odd reason, on one of the computers (the one that has the email that these pdf's come from) doesn't show them with the pdf icon on the desktop.  It has the green corel draw icon instead.


THANKS in advance