Error during creating security store for Oracle Access Manager 11.1.2.1.1

Although it worked with the exact same software versions, I today faced an error while creating the database security store for Oracle Access Manager 11.1.2.1.1

[oracle@server ~]$ $MWH/oracle_common/common/bin/wlst.sh /oracle/identity0/mwh/identity0/common/tools/configureSecurityStore.py -d /oracle/identity0/projects/domains/iamdomain -c IAM -p ***password*** -m create
CLASSPATH=/oracle/identity0/mwh/patch_wls1036/profiles/default/sys_manifest_classpath/weblogic_patch.jar:/oracle/identity0/mwh/patch_ocp371/profiles/default/sys_manifest_classpath/weblogic_patch.jar:/oracle/jrockit/jrockit-jdk1.6.0_45-R28.2.7-4.1.0-linux-x64/lib/tools.jar:/oracle/identity0/mwh/wlserver_10.3/server/lib/weblogic_sp.jar:/oracle/identity0/mwh/wlserver_10.3/server/lib/weblogic.jar:/oracle/identity0/mwh/modules/features/weblogic.server.modules_10.3.6.0.jar:/oracle/identity0/mwh/wlserver_10.3/server/lib/webservices.jar:/oracle/identity0/mwh/modules/org.apache.ant_1.7.1/lib/ant-all.jar:/oracle/identity0/mwh/modules/net.sf.antcontrib_1.1.0.0_1-0b2/lib/ant-contrib.jar::/oracle/identity0/mwh/oracle_common/modules/oracle.jrf_11.1.1/jrf-wlstman.jar:/oracle/identity0/mwh/oracle_common/common/wlst/lib/adfscripting.jar:/oracle/identity0/mwh/oracle_common/common/wlst/lib/adf-share-mbeans-wlst.jar:/oracle/identity0/mwh/oracle_common/common/wlst/lib/mdswlst.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/auditwlst.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/igfwlsthelp.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/jps-wlst.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/jrf-wlst.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/oamap_help.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/oamAuthnProvider.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/ossoiap_help.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/ossoiap.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/ovdwlsthelp.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/sslconfigwlst.jar:/oracle/identity0/mwh/oracle_common/common/wlst/resources/wsm-wlst.jar:/oracle/identity0/mwh/utils/config/10.3/config-launch.jar::/oracle/identity0/mwh/wlserver_10.3/common/derby/lib/derbynet.jar:/oracle/identity0/mwh/wlserver_10.3/common/derby/lib/derbyclient.jar:/oracle/identity0/mwh/wlserver_10.3/common/derby/lib/derbytools.jar::
Initializing WebLogic Scripting Tool (WLST) ...
Welcome to WebLogic Server Administration Scripting Shell
Type help() for help on available commands
Info: Data source is: opss-DBDS
Problem invoking WLST - Traceback (innermost last):
  File "/oracle/identity0/mwh/identity0/common/tools/configureSecurityStore.py", line 896, in ?
TypeError: cannot concatenate 'str' and 'NoneType' objects

It seems this is caused by JRockit. After switching to jdk1.7.0_40 everything worked fine.