tsteinmaurer on "How to run stress.jar tool in DSE 3.1"

I'm failing to run the stress.jar tool with DSE 3.1. This is what I have tried:

In /usr/share/dse:

sudo ./dse.in.sh
sudo java -cp $CLASSPATH org.apache.cassandra.stress.Stress

I end up with the following error message:
Class not found: class org.apache.cassandra.thrift.TFramedTransportFactory

Any ideas?