How to fix 'Failing to build model' error?

[saba-zones]

I am using a bunch of HTML pages saved without any extension (i.e. as plain text) in my positive and negative directories of train_data folder. Now when I run buildModel command to train a new model based on my provided dataset, a new temporary file "smile_input.arff' is prepared but it fails to generate features, model and final pageclassifier.yml file. I am running into this issue. Can someone help me debug this?

Moreover, I am using docker image vidanyu/ache:master

[saba-zones]

To add more to this, when I test the same command for provided sample_training_data in /config directory, I run into this issue there as well. But after deleting some of the sample files, if I run this command again, it is able to build the model for me.

This means it works for few samples, but at same time does not for few, and I cannot identify what difference in sample files is causing this.