I solved a very similar issue by changing the display type to "Entity Reference" (not "Entity Reference View Widget") and using using the ER Widget only for the view checkbox selection field.

[Here is a detailed step-by-step guide][1] to a solution which worked for me using the latest Drupal 7 dev version of the ER Widget module.


  [1]: http://drupal.stackexchange.com/questions/24559/tagging-a-friend-in-a-node/100933#100933