XML import failed with ConstraintViolationException in SQL Server or Oracle

2011-08-10 10:34:40,674 ERROR [Importing data task] [confluence.importexport.xmlimport.BackupImporter] importEntities Cannot import the entities: 
 -- referer: http://localhost:8359/setup/setup-restore-start.action | url: /setup/setup-restore.action | userName: anonymous | action: setup-restore
com.atlassian.confluence.importexport.ImportExportException: Unable to complete import because the data does not match the constraints in the Confluence schema. Cause: SQLException: Violation of UNIQUE KEY constraint 'cp_unique_user_groups'. Cannot insert duplicate key in object 'dbo.CONTENT_PERM'.
	at com.atlassian.confluence.importexport.xmlimport.DefaultXmlImporter.doImport(DefaultXmlImporter.java:57)
	at com.atlassian.confluence.importexport.xmlimport.BackupImporter.importEntities(BackupImporter.java:237)
	at com.atlassian.confluence.importexport.xmlimport.BackupImporter.importEverything(BackupImporter.java:181)
	at com.atlassian.confluence.importexport.xmlimport.FileBackupImporter.importEverything(FileBackupImporter.java:108)
	at com.atlassian.confluence.importexport.xmlimport.BackupImporter.doImportInternal(BackupImporter.java:108)
	at com.atlassian.confluence.importexport.Importer.doImport(Importer.java:74)
	at com.atlassian.confluence.importexport.DefaultImportExportManager.importAs(DefaultImportExportManager.java:74)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
	at $Proxy83.importAs(Unknown Source)
	at com.atlassian.confluence.importexport.actions.ImportLongRunningTask.runInternal(ImportLongRunningTask.java:55)
	at com.atlassian.confluence.util.longrunning.ConfluenceAbstractLongRunningTask.run(ConfluenceAbstractLongRunningTask.java:21)
	at java.lang.Thread.run(Thread.java:662)
Caused by: net.sf.hibernate.exception.ConstraintViolationException: could not insert: [com.atlassian.confluence.security.ContentPermission#753668]
	at com.atlassian.confluence.importexport.xmlimport.parser.BackupParser.endElement(BackupParser.java:53)
	at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source)
	at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanEndElement(Unknown Source)
	at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
	at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
	at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
	at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
	at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
	at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
	at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
	at org.apache.xerces.jaxp.SAXParserImpl.parse(Unknown Source)
	at javax.xml.parsers.SAXParser.parse(SAXParser.java:198)
	at com.atlassian.confluence.importexport.xmlimport.DefaultXmlImporter.parseBackup(DefaultXmlImporter.java:93)
	at com.atlassian.confluence.importexport.xmlimport.DefaultXmlImporter.doImport(DefaultXmlImporter.java:45)
	... 20 more
Caused by: net.sf.hibernate.exception.ConstraintViolationException: could not insert: [com.atlassian.confluence.security.	#753668]
	at net.sf.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:62)
	at net.sf.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
	at net.sf.hibernate.persister.AbstractEntityPersister.convert(AbstractEntityPersister.java:1331)
	at net.sf.hibernate.persister.EntityPersister.insert(EntityPersister.java:472)
	at net.sf.hibernate.persister.EntityPersister.insert(EntityPersister.java:436)
	at net.sf.hibernate.impl.ScheduledInsertion.execute(ScheduledInsertion.java:37)
	at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2447)
	at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2433)
	at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2390)
	at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2259)
	at com.atlassian.confluence.importexport.xmlimport.ImportProcessorContext.flushIfNeeded(ImportProcessorContext.java:212)
	at com.atlassian.confluence.importexport.xmlimport.ImportProcessorContext.saveObject(ImportProcessorContext.java:256)
	at com.atlassian.confluence.importexport.xmlimport.persister.ReflectiveObjectPersister.persist(ReflectiveObjectPersister.java:119)
	at com.atlassian.confluence.importexport.xmlimport.DefaultImportProcessor.persist(DefaultImportProcessor.java:42)
	at com.atlassian.confluence.importexport.xmlimport.DefaultImportProcessor.processObject(DefaultImportProcessor.java:32)
	at com.atlassian.confluence.importexport.xmlimport.parser.BackupParser.endElement(BackupParser.java:49)
	... 33 more
Caused by: java.sql.SQLException: Violation of UNIQUE KEY constraint 'cp_unique_user_groups'. Cannot insert duplicate key in object 'dbo.CONTENT_PERM'.
	at net.sourceforge.jtds.jdbc.SQLDiagnostic.addDiagnostic(SQLDiagnostic.java:368)
	at net.sourceforge.jtds.jdbc.TdsCore.tdsErrorToken(TdsCore.java:2816)
	at net.sourceforge.jtds.jdbc.TdsCore.nextToken(TdsCore.java:2254)
	at net.sourceforge.jtds.jdbc.TdsCore.getMoreResults(TdsCore.java:631)
	at net.sourceforge.jtds.jdbc.JtdsStatement.processResults(JtdsStatement.java:584)
	at net.sourceforge.jtds.jdbc.JtdsStatement.executeSQL(JtdsStatement.java:546)
	at net.sourceforge.jtds.jdbc.JtdsPreparedStatement.executeUpdate(JtdsPreparedStatement.java:505)
	at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:105)
	at net.sf.hibernate.impl.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:22)
	at net.sf.hibernate.persister.EntityPersister.insert(EntityPersister.java:462)
	... 45 more