Import Outlook PST file

Hi,
I had to reformat my win 98 computer, before I did so I exported my Office 2000 outlook express files to a pst file and burned it to a cd with the other files i had.
When I reloaded my system I up graded from win 98 to win 2000 pro and I went to Outlook 2000 in sted of outlook express 2000. When I am trying to inport my Outlook pst files it says i do not have permission. I am not on a network. Does anyone know what i am dong wrong? Can I get my e-mails back?