I think the thing that you are missing is an understanding of how stacked bar/column/line charts work. The first series is charted its value to the right of the x axis. The second series is plotted its value above the end of the first series, and so on. So, as you have it set up, the chart is plotting the first bar 42000+ days, then adding and additional 42000+ days to get the second bar, and so on.

What you need is the differences calculated in the spreadsheet. I would probably proceed as follows:

1) In G2, enter =B2. copy down
2) In H2, enter =C2-B2 copy H2 down and across.
3) Adjust series in chart so that chart is based on G2:J2 instead of B2:E2.
4) Adjust data labels to reflect the dates, as desired, or remove the data labels. If you are using 2013 or later, the option to select cell data for data labels is built into Excel. If you are using a version earlier than 2013, you will want to download Rob Bovey's XY chart labeler add-in to get this functionality.

Where do you get stuck?