The format of MS Outlook mail archives (*.pst) is protected by Microsoft.
Therefore, to access a PST file, this file must be accessible from MS Outlook as a
mail folder. 

MS outlook (*.pst) is different from outlook express (*.dbx). You can extract emails directly from *.dbx file. But from *.pst, this is not possible - according to Microsoft - unless you save these files as comma-separated-values (*.CSV).

To collect email from outlook you need to export the data in a text (comma-separated-values (*.CSV)) file.

To export, do the following, step by step:

1) Open the application MS Outlook.

2) Select the menu command: File | Import and Export...

3) Select: Export to a file.

4) In the next dialogue, select: Comma Separated Values.

5) Select the folder (e.g. Inbox, Sent Items etc.) to Export from

6) Give a file name and path (e.g. c:\inbox.txt) to Save

Then use offline email extractor program and select that file to extract emails from there.