I have windows XP and I recently installed a 9 version of Adobe Acrobat Reader. Since then a receive the following error message: "The Adobe Acrobat/Reader that is running can not be used to view PDF files in a Web Browser. Adobe Acrobat/Reader version 8 or 9 is required." I had installed the 9 version. Any idea why this is happening or more importantly, what should I do to fix it?