jQuery Grid Plugin - jqGrid

I'm having trouble saving dates back to mysql db. The grid I have shows the date correctly after I press enter (after performing the inline edit), but then when I refresh the entire page and the grid requeries the db, I can see that the new date was never saved, but instead the date shows up as 1970-01-01.

I noticed this is also the case with the jgGrid Demo:

http://www.trirand.net/demophp.aspx

- From the menu on left, select "Edit, Add, Delete, Rows"

- Then select "Inline Editing - autocomplete, datepicker"

Try to change the date! The grid will display it accurately after pressing enter, but then when you refresh the page, it will just go to 1970-01-01.

Please help! I need to be able to edit my dates! If someone could just show me why the demo isn't working, I could probably apply it to my code too.