I am getting below message for one of the dashlet "only a single measurement available which cant be visualized by any area chart type " please let me know what it means .
Pretty much what it says. For the measure you are charting, and for the timeframe you are looking at, only one value has been registered so far, so you can't visualise that in an area chart (whether area or stacked area) because there can't be an area with just one dot on the chart.
So, try extending the timeframe or changing the type of the chart to lines, bars, or some other representation and then you will see your value. Alternatively, over time, that measure should start registering more values so at a later point in time you might be able to plot a whole area on the chart.
Thanks for the response , i have changed the chart type to line now . the measure is for response times not sure even though the application has count only the response times dashlet shows the message , means that response times is too low that it is not showing up .