I cannot open any .pdf files. When I try to open a .pdf file in the Web browser it gives me an error message "Could not find Acrobat External Window Handler". When I try to open a pdf file directly in Acrobat Reader it gives me an error message saying "There was an error opening this document. A temporary file could not be opened." I already tried uninstalling and completely cleaning out Adobe and then reinstalling it but it did not work. I am using Adobe Acrobat Reader 5.0 on Windows 2000 Pro. We are on a Microsoft Exchange Server 2000 if that matters. I tried some of the solutions on the Adobe website for this problem however they did not work.