I'm having trouble importing relationships in the newly released v1.5 (running on Drupal). I can recreate this bug on my local installation, and on the demo codebase running on the CiviCRM site.
Here are the steps I'm following:
1. Import household records with legacy External Identifier - SUCCESS
2. Import individual records
a. map records as "household member" of "External Identifier" FAILURE
b. map records as "household member" of "Household name" FAILURE
c. map records as "household member" of "Email" FAILURE
All three mapping options above fail to create the relationship. Individual records are created, but the relationship is not. I've attached the sample data file I'm working with (two records).