000978 : There are too few vertices to create a valid geometry.
An unexpected error occurred while constructing the ellipse or circle feature. This can occur if there are too few noncoincident features with valid weights to create the output feature. For example, at least two features are required to create a circle and at least three are required to create an ellipse.
Make sure that the input feature class has sufficient noncoincident points to construct the output feature geometry. If you specify a Case Field, make sure there are sufficient noncoincident input features for all of the individual cases. If you specify a Weight Field, make sure that there are sufficient non-null and nonzero weights to construct the output feature geometry. Input features with Null values are not used in the analysis.