Getting classcast exception on running bin/queryWithLDA

[rrgirish]

I ran Mallet on my input data and converted that to the 4 files required to run LDA.

However, bin/queryWithLDA requires an Lucene index(which can be created with the bin/indexDirectory command) and a LDA index( I substituted the mallet file) and put the 4 files in the query folder and ran it.

After this i get
java.lang.ClassCastException: cc.mallet.types.InstanceList cannot be cast to ca.queensu.cs.sail.lucenelda.LDAHelper
at ca.queensu.cs.sail.lucenelda.LDAQueryAllInDirectory.main(LDAQueryAllInDirectory.java:153)
Exception in thread "main" java.lang.NullPointerException
at ca.queensu.cs.sail.lucenelda.LDAQueryAllInDirectory.main(LDAQueryAllInDirectory.java:160)

Any idea on how to proceed with this?