Help please,

At first my outlook start blocking when downloading emails and did not want to download big attachments. I did the following ending up with big problems.

I selected a number of old emails from Outlook Mac to export them to a external hard disk. 

Asked to delete the mails after export.  When done it seems "all" emails where gone, also the ones I did not wanted to export.

When trying to import them again I get below message :

I see the folder on my external hard disk but can not get them imported anymore.

Can some one help please?  Thanks.