Plugin eChart error (bar chart not appearing)

Hi,

I recently discovered a new plugin called eChart which can produce the chart with filters, but when I tried to implement it, it did not show the bar graphs for certain number values but for other types of number values with numbers in it will be able to display the bar graphs.

My question is:

1.  Why the bar graphs only will be able to display if the number values would have numbers in them and not the other types of number values?

2. Is there any way to display the bar graphs for certain number values that do not have numbers in them?