with ruby pda.get_cov() error

qda.sg

CSVFile f_feats_train("../../data/classifier_4class_2d_linear_features_train.dat")
CSVFile f_feats_test("../../data/classifier_4class_2d_linear_features_test.dat")
CSVFile f_labels_train("../../data/classifier_4class_2d_linear_labels_train.dat")
CSVFile f_labels_test("../../data/classifier_4class_2d_linear_labels_test.dat")

#![create_features]
RealFeatures features_train(f_feats_train)
RealFeatures features_test(f_feats_test)
MulticlassLabels labels_train(f_labels_train)
MulticlassLabels labels_test(f_labels_test)
#![create_features]

#![create_instance]
QDA qda(features_train, labels_train)
#![create_instance]

#![train_and_apply]
qda.train()
MulticlassLabels labels_predict = qda.apply_multiclass(features_test)
#![train_and_apply]

#![extract_mean_and_cov]
int classlabel = 1
RealVector m = qda.get_mean(classlabel)
RealMatrix c = qda.get_cov(classlabel)
#![train_and_apply]

#![evaluate_accuracy]
MulticlassAccuracy eval()
real accuracy = eval.evaluate(labels_predict, labels_test)
#![evaluate_accuracy]

# additional integration testing variables
RealVector output = labels_predict.get_labels()

$ ruby ruby/classifier/qda.rb

/Library/Ruby/Site/2.0.0/universal-darwin14/modshogun.bundle: warning: rb_define_const: invalid name `__MAC_10_8' for constant
[ERROR] In file /Users/zora/Github/shogun/src/shogun/io/File.cpp line 71: Error opening file '../../data/classifier_4class_2d_linear_features_train.dat'
ruby/classifier/qda.rb:3:in `initialize': [ERROR] In file /Users/zora/Github/shogun/src/shogun/io/File.cpp line 71: Error opening file '../../data/classifier_4class_2d_linear_features_train.dat' (fatal)
    from ruby/classifier/qda.rb:3:in `new'
    from ruby/classifier/qda.rb:3:in `<main>'

this error comes from file not found, as the error says. So the path is probably wrong.
Can you post the generated ruby listing as well. I get a different error when trying to reproduce locally