Data export import failed to import into Drupal 7
It is possible you can't since this module wasn't created for 6-7 migration. (It's too bad, too.)
From the Data Export Import project page:

NB - This module has primarily been developed to move data between the same versions of Drupal - to move data between a live site and a development/beta site.
It may be possible that the taxonomy terms and users data files exported from Drupal 6 can be imported into a Drupal 7 site (or the other way around). This has not been tested yet and any feedback would be gratefully received.

You could try contacting the maintainer through the issue queue, see if it's a small thing they can fix, but since the project is currently looking for a new maintainer I wouldn't expect a quick response.