Hey Sarah,
Did you ask printer what version of AI he or she has? I believe x3 will default to cs2 or cs3. This means if your printer has cs or older version of AI he will not be able to open. Like most graphic programs there is an option to down save files to previous versions in corel. Its usually in one of the dialog boxes that appear when you choose save as. Also If you have illustrator yourself you can try opening it before sending. Or just upload it here and someone with cs 3 try and open it.
Did you ask printer what version of AI he or she has? I believe x3 will default to cs2 or cs3. This means if your printer has cs or older version of AI he will not be able to open. Like most graphic programs there is an option to down save files to previous versions in corel. Its usually in one of the dialog boxes that appear when you choose save as. Also If you have illustrator yourself you can try opening it before sending. Or just upload it here and someone with cs 3 try and open it.