It\'s drives me crazy.. Last hour I am trying to figure out why my report stopped to worked right after I added a subreport to it.. I already checked and tried all similar
try to send SUBREPORT_DIR parameter from code. Maybe it is missing... if you use maven, check resource directory tag in pom.xml and compare them.
params.put("SUBREPORT_DIR", "reports/report/blablaFolder/");