HEAD CVS drupal repository is empty

Yes. The HEAD is always empty (only a README.txt file). Use DRUPAL-6--1.

From the README.txt:

Currently there is no HEAD version of the Node import module. Please use the
latest stable release from http://drupal.org/project/node_import for your
specific Drupal version.

See http://drupal.org/node/17570 as to why this approach was taken.

A new HEAD version of node_import compatible with Drupal 5.x will be created
shortly. The planned timeframe for this is Februari 12th 2007. Estimated
timeframe for a usuable 5.x release is Februari 17th 2007.

(Note that I should edit this README.txt to indicate the latest version is Drupal 6.x).

Fixed.