Adding a Dimension causes NPE in OLAP query #45

The following NPE was thrown when I was adding a 2nd dimension to the OLAP 
query. The Dimension has 2 differen hierarchies:

java.lang.NullPointerException
    at 
ca.sqlpower.wabit.olap.OlapResultSet.determineRowAxisColumns(OlapResultSet.
java:286)
    at 
ca.sqlpower.wabit.olap.OlapResultSet.populate(OlapResultSet.java:147)
    at 
ca.sqlpower.wabit.olap.OlapQuery.fireResultSetEvent(OlapQuery.java:496)
    at 
ca.sqlpower.wabit.olap.OlapQuery.executeOlapQuery(OlapQuery.java:361)
    at 
ca.sqlpower.wabit.swingui.olap.OlapGuiUtil$1.doStuff(OlapGuiUtil.java:53)
    at ca.sqlpower.swingui.SPSwingWorker.run(SPSwingWorker.java:104)
    at java.lang.Thread.run(Unknown Source)