Looking at your code it seems as if you have set the type of one series to be "Pie" which would not grant you a normal X/Y axis graph. If you want to combine both a Pie chart and a "normal" chart I suggest using two separate charts for this. In order to have two separate series of different types (like a Line chart and a Bar chart) you can do something like this:
ASPX:
There is also a documentation article, found
here, which goes over this :)