Ireport 5.1.0 compatibility with JasperReports 3.7.6

[elizabeth.winter]

Our customer just upgraded iReport to 5.1.0 from 4.01, however JasperReports still remains at version 3.7.6.   I set the compatibility mode in iReport 5.1.0 to 3.7.5 since it doesn't have 3.7.6 (hmm, is this a hint) in the list of versions.  When I run a jasper report compiled under the new 5.1.0 version (with compatibility of 3.7.5), I get one of two runtime exceptions:

JRFillSubrepo E net.sf.jasperreports.engine.fill.JRFillSubreport prepare Fill 1769455273: exception

                                 java.lang.NullPointerException

at net.sf.jasperreports.engine.fill.JRFillImage.evaluateImage(JRFillImage.java:1034)

at net.sf.jasperreports.engine.fill.JRFillImage.evaluate(JRFillImage.java:1004)

at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:258)

at net.sf.jasperreports.engine.fill.JRFillBand.evaluate(JRFillBand.java:499)

at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillTitle(JRVerticalFiller.java:326)

 

 

JRFillSubrepo E net.sf.jasperreports.engine.fill.JRFillSubreport prepare Fill -723376141: exception

                                 java.lang.NullPointerException

at java.lang.Class.isAssignableFrom(Native Method)

at net.sf.jasperreports.engine.fill.JRFillTextField.getFormat(JRFillTextField.java:706)

at net.sf.jasperreports.engine.fill.JRFillTextField.evaluateText(JRFillTextField.java:394)

at net.sf.jasperreports.engine.fill.JRFillTextField.evaluate(JRFillTextField.java:368)

at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:258)

 

Obviously there is some capatibility issue.  However everyting I have read, says the versions are backwards compatible.  Is there something else I need to do?

 

Thanks in advance!