Date Format for Excel Connector?

I've uploaded a series of events using Excel Connector, and even though the due date was in the 01/01/2001 format, all of the dates imported show up as 12/30/1899.

I've tried updating with other date formats, but nothing makes a difference - they all show up the same way; 12/30/1899.

Any suggestions on how to update these to the correct dates?