Cannot compile studio reports with HTML5 chart

Hi all.

I have installed JAspersoft Studio Pro 5.6 final on my computer (windows 32 bits version)

When I create a report with a HTML5 chart, I systematically got the following compilation error:

net.sf.jasperreports.engine.JRException: Errors were encountered when compiling report expressions class file:
1. Only a type can be imported. com.jaspersoft.ji.adhoc.service.AdhocEngineServiceImpl resolves to a package
import com.jaspersoft.ji.adhoc.service.AdhocEngineServiceImpl;
       <---------------------------------------------------->
1 errors


    at net.sf.jasperreports.engine.design.JRAbstractCompiler.compileReport(JRAbstractCompiler.java:204)

    at net.sf.jasperreports.eclipse.builder.JasperReportCompiler.compileReport(JasperReportCompiler.java:172)

    at com.jaspersoft.studio.editor.preview.view.control.ReportControler.compileJasperDesign(ReportControler.java:394)

    at com.jaspersoft.studio.editor.preview.view.control.ReportControler.access$14(ReportControler.java:382)

    at com.jaspersoft.studio.editor.preview.view.control.ReportControler$4.run(ReportControler.java:315)

    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)

Is any library missing? (I did not change the preinstalled libraries)

This also happens when trying to preview reports created from ahdoc view from jasperreport server  (also using HTML5 charts)

Can anyone help me on that subject?

Thanks a lot.