Problem with line charts in Excel 2007

I have a line chart that I have created comparing different organizations data by month. The chart, for some reason, seems to add up the numbers of each organization and provides a false chart. When I change the chart type to Bar chart, it is displayed correctly, but I need it in a line chart view. See attached sample.

It's the wrong type of line graph. You want the "line graph" not the "stacked line graph".