PRD - Preview button - error message from report based on res.partner model

[disna-sistemas]

Hi,
I have a clean new report with id and name fields
The data source is based on standard search, res.partner model (Odoo 8.0)
I have tested with other models and there is no problem but when i try res.partner i get this:

org.pentaho.reporting.engine.classic.core.ReportDataFactoryException: java.lang.Integer cannot be cast to [Ljava.lang.Object;
at org.pentaho.reporting.engine.classic.extensions.datasources.openerp.OpenERPDataFactory.queryData(OpenERPDataFactory.java:201)
at org.pentaho.reporting.ui.datasources.openerp.OpenERPDataSourceEditor$OpenERPPreviewWorker.run(OpenERPDataSourceEditor.java:288)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to [Ljava.lang.Object;
at com.debortoliwines.openerp.api.ObjectAdapter.searchAndReadObject(ObjectAdapter.java:516)
at com.debortoliwines.openerp.api.ObjectAdapter.searchAndReadObject(ObjectAdapter.java:498)
at com.debortoliwines.openerp.reporting.di.OpenERPHelper.getSearchData(OpenERPHelper.java:232)
at com.debortoliwines.openerp.reporting.di.OpenERPHelper.getData(OpenERPHelper.java:86)
at org.pentaho.reporting.engine.classic.extensions.datasources.openerp.OpenERPDataFactory.queryData(OpenERPDataFactory.java:197)
... 2 more

Any idea?
Thanks in advance,

Victor Martin