When importing an .ARD file into Adobe® Illustrator® CS6/CC the layers palette will show the imported .ARD layer but does not show its sub-layers. There are no issues when importing this file to Adobe® Illustrator® CS5.
Place an .ARD file in AICS6 or AICC. The sub-layers for the .ARD file sometimes do not show in the Layers palette.
This is an Adobe® Illustrator® issue. See these articles on Adobe's Website: