What part of this error message can be unclear? Let's see…
In first line, you use this function:
https://msdn.microsoft.com/en-us/library/w3f99sx1%28v=vs.110%29.aspx[
^].
I have no idea why, but you were lucky enough to have this string recognized as some really existing type. But what type? As the exception tells you, the abstract one. What to do? Whatever you want. 1) leave your code as is: it behaves correctly, giving you quite expected response to your string; 2) change this string to the string representing some non-abstract non-static class name, 3) modify the same class, make it non-abstract and non-static.
—SA