I've been using using the C45Learning algorithm and it has been working great. Recently, I added data to the dataset and recalculated and I get this error:

"An exception of type 'System.InvalidOperationException' occurred in Accord.MachineLearning.dll but was not handled in user code

Additional information: The tree is degenerated. This is often a sign that the tree is expecting discrete inputs, but it was given only real values."

Can anyone provide some insight as to what is causing this? Does this mean that items in my dataset are too similar and the algorithm is not able to distinguish between them?

Any help is greatly appreciated.