Text invisible

Hi, at work we send out a pdf form to be filled out and emailed back to us. For those that have Acrobat, other wise they fax it back. In many cases, the text that is entered, we can't see unless we click the 'highlight' button, but when un highlighted, the text goes away. It will not print the added text either. We just can't figure out. We are on XP, Office 2007. We are not that knowledgeable about Acrobat, so help is needed. Thanks so much. Update on the product, it is Acrobat Professional 8.1.3

Or, if you don't hightlight the entire form, and just click on a field, the text will come up, but when you click off into another field, that previous text will go away and only the text that is in the field you are clicking in will be visible.