[xwiki-users] Problems with importing document into xwiki 2.1

Hi, We are having problem with importing document from xwiki 1.9 into 2.1. (Most of the data in 1.9 was previously imported from v1.7). Any insight will be appreciated. In the log file, there are SQL errors: ERROR 2010-02-09 15:20:23,022 (Package.java:628) - Failed to save document ABCD.System Management Plan (SMP) WARN 2010-02-09 15:20:23,084 (JDBCExceptionReporter.java:77) - SQL Error: 1400, SQLState: 23000 ERROR 2010-02-09 15:20:23,084 (JDBCExceptionReporter.java:78) - ORA-01400: cannot insert NULL into ("XWIKI"."XWIKIOBJECTS"."XWO_CLASSNAME") ERROR 2010-02-09 15:20:23,084 (AbstractFlushingEventListener.java:301) - Could not synchronize database state with session org.hibernate.exception.ConstraintViolationException: could not insert: [com.xpn.xwiki.objects.BaseObject] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71) Thanks Jin