Hive action with python transformer won't start

Hi all,
I have a workflow.xml with 2 hive actions. The first hive action has a transform action using java code. By appending the JAR file this action gets executed without problems.
The second action is also hive but using a TRANSFORM function written in python.
Oozie makes the call but then the jobs hangs hours on end without processing a single line (normal execution time is 20 minutes). Both jobs work fine without using oozie.
Configuration of second script looks like this:
…
<hive xmlns=”uri:oozie:hive-action:0.2″>
<job-tracker>${jobTracker}</job-tracker>
<name-node>${nameNode}</name-node>
<script>/p0_custom/custom/hive/sql/osix_pivot_imsi.sql</script>
<param>DATA_OUTPUT_MASK=${DATA_OUTPUT_MASK}</param>
</hive>
…
Python script is registered in the sql script but oozie won’t execute. Do I need to configure the python script as a streaming action?

Thanks for any insights.