Jasper Reports Openerp

I create a master report for account_invoice that have a subreport where i print some information about account_invoice_line and account_invoice_line_tax.

I use P{REPORT_CONNECTION}, the parameter in subreport to connect to the master report by id of object of the main report. When i test in jasper the things goes right, but in a pass to openerp the following mistake appears:
'Failed to invoke method execute in class com.nantic.jasperreports.JasperServer: null'
and one warning that appears is the following:
WARNING new_BD openerp.addons.jasper_reports.JasperReports.BrowseDataGenerator: Field '' (path: ) does not exist in model 'account.invoice'.
Can you help me?
Best regards,
José