Restoring a backup of an older version of Confluence (older than build 1012) will cause the osUserToAtlassianUserMigrationUpgradeTask to be run. The OSUEntityMigrator used in this class includes embedded SQL which has upper case table and column names. The BucketPropertySetItem.hbm.xml which defines these tables uses lower case so where the database is case sensitive these queries fail, resulting in a failure of the site import.

This was found during pre-release testing of Confluence 2.8 on SQL Server 2005.