Hi Nancy,
No worries. We will get to the bottom of this. You should definitely make sure that you have Reader XI installed for starters (the current version is 11.0.07 and there were some updates to that that improve the ExportPDF experience).
So, whether you convert TO or FROM PDF using Adobe PDF pack, converted files are stored in your online Acrobat.com account. Are you trying to open the files directly from your online account, or downloading them to your desktop and opening from there? If you're previewing them online, what web browser are you using? And do you receive any sort of error when you try to open the files?
Please describe to me the process that you're using, so I can understand where things fall apart.
Best,
Sara