"Problem with Simple Decision Tree Analysis"

I just downloaded RapidMiner and am evaluating it for some data mining work we are doing.  I went through the tutorials and choose a a simple decision tree exercise with some actual usage data that I have  (1300 users, 16 attributes, predict use of one tool).  I get the Use variable split (100/1200) as a result of the DecisionTree operator but no partitions.  Have checked and data is being read fine, parameters all look consistent witn the tutorial examples.  I must be missing something obvious.

Any help gratefully accepted,

Dr. Richard Y Flanagan
Rohm and Haas Company