Exception when running Titanic Binary Classification

[cuauty]

Hi, Team,

The issue looks like this issue. I follows the latest version to try it. Thanks.

The original content kept as the follows for reference in the future.

I am new comer of TransmogrifAI and working on running Titanic Binary Classification according to the link. Unfortunately when I try to train by "gradlew sparkSubmit ..." I meet the following exception:
Exception in thread "main" java.lang.RuntimeException: Failed to write out stage 'FeatureGeneratorS tage_000000000005' at com.salesforce.op.stages.OpPipelineStageWriter.writeToJson(OpPipelineStageWriter.scala:8 1) at com.salesforce.op.OpWorkflowModelWriter$$anonfun$3.apply(OpWorkflowModelWriter.scala:134) at com.salesforce.op.OpWorkflowModelWriter$$anonfun$3.apply(OpWorkflowModelWriter.scala:134) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234) at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186) at scala.collection.TraversableLike$class.map(TraversableLike.scala:234) at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:186) at com.salesforce.op.OpWorkflowModelWriter.stagesJArray(OpWorkflowModelWriter.scala:134) at com.salesforce.op.OpWorkflowModelWriter.stagesJArray(OpWorkflowModelWriter.scala:111) at com.salesforce.op.OpWorkflowModelWriter.toJson(OpWorkflowModelWriter.scala:86) at com.salesforce.op.OpWorkflowModelWriter.toJsonString(OpWorkflowModelWriter.scala:71)
My command to run this case is
gradlew sparkSubmit -Dmain=com.salesforce.app.Titanic -Dargs="--run-type=train --model-location=/tmp/titanic-model --read-location Passenger=/root/transmog/test-data/PassengerDataAll.csv"
and before I start I have run the test command gradlew compileTestScala installDist
successfully.

My environment is Linux X64 (CentOS), and my spark runs as same computer with 32 cores and 64 GB memory.

Any comments are welcome and thanks a lot.

Chris Ding