Remember that Outlook Express is a totally different program to Outlook, the
names can be thought of as deceptive/misleading, there is *no* relationship
like Outlook Express being a cut down Outlook.
Outlook Express does have an Export option (to Outlook), this is *not* the
same as archiving.
I've never tried what you want to do before but I just tried an export from
OE to Outlook (*not* an archive!)- so easy and straight forward! Open
Outlook Express, File, Export, Messages. Choose Outlook. Wait. Open Outlook
and there they were- no looking for the files, importing or anything else-
automatically in the program.
It seems you should import the archived messages back into OE, and with
Outlook installed on the same computer use Export to Outlook. It doesn't
seem that archived files from what is a totally different program to Outlook
can be handled, and I doubt it would be as easy as the Export function.