I did a fresh install of JRS 5.5.0 on apache-tomcat-7.0.52, JVM 1.7_51, Debian 7.4 Wheezy and I too am unable to save any scheduled reports. Once all criteria is entered and SAVE is executed the error fires in the Catalina.out. Will need to leave my JRS 4.7 running in order modify and execute scheduled reports of which i have many.