Importing into date fields with Administrator Import tool

I am trying to import an excel spreadsheet into SBM 2009 R4. Most fields worked fine (including Single Selection and Relational) but the date fields are not coming through correctly.

All the dates imported with the year 1900 and the months and dates seemed to all turn to sometime in January. For instance, 10/1/2011 turned into 1/06/1900, 7/29/2012 turned into 1/07/1900, etc.

What am I doing wrong?