I have upgraded a test server from 5.5 to 5.7.1 and when I start the new version I achieve warnings like these:

2013-07-11 14:10:56,952 WARN  [org.nuxeo.ecm.core.api.TransactionalCoreSessionWrapper] Session invoked in a container without a transaction active: turn on debug logs for more information about the faulty call.
2013-07-11 14:10:56,955 DEBUG [org.nuxeo.ecm.core.api.TransactionalCoreSessionWrapper] Session invoked in a container without a transaction
java.lang.Throwable
at org.nuxeo.ecm.core.api.TransactionalCoreSessionWrapper.checkTxActiveRequired(TransactionalCoreSessionWrapper.java:104)
at org.nuxeo.ecm.core.api.TransactionalCoreSessionWrapper.invoke(TransactionalCoreSessionWrapper.java:130)
at com.sun.proxy.$Proxy45.queryAndFetch(Unknown Source)
at org.nuxeo.ecm.platform.relations.CoreGraph$SizeFinder.run(CoreGraph.java:213)
at org.nuxeo.ecm.core.api.UnrestrictedSessionRunner.runUnrestricted(UnrestrictedSessionRunner.java:156)
at org.nuxeo.ecm.platform.relations.CoreGraph.size(CoreGraph.java:191)
at org.nuxeo.ecm.platform.relations.services.RelationService$1.run(RelationService.java:527)

It is possible to fix it ?