when i try to import my pst file, i see a message saying pst file is corrupted or not a pst file

when i try to import my pst file, i see a message saying pst file is corrupted or not a pst file.
so i used a pst fixing file to fix my pst file, and it did not work.
i am sure that the file i am trying to import is a pst file.
i created a blank pst file for the test import, and the same message pops up.
please help me.
thanks.