PDFMaker Gives "MAPI Logon Unsuccessful....."

I have spent hours trying to do a mail merge using PDFMaker in Word 2007 but keep getting a "MAPI Logon Unsuccessful" error message. I am using Acrobat X Pro, Office 2007, Vista SP2 and Wiindows Mail. I am able to produce the full mail merge in Word and the documents attach and send emails succesfully but I need to produce them in .pdf. I also had this problem in earlier Acrobat versions but had hoped that buying Pro X would resolve this MAPI issue. There is very little information on line about this error. Anyone have any ideas?