The specific errors being dealt with here are:
11/26/19 4:05 AM (ExecTask) log4j:ERROR Could not create the Layout. Reported error follows.
11/26/19 4:05 AM (ExecTask) java.lang.ClassNotFoundException: com.niku.blobcrack
11/26/19 4:05 AM (ExecTask) Error Applying XOG: Failed to initialize logger
11/26/19 4:05 AM (ExecTask) com.niku.union.config.ConfigurationException: Error unmarshalling config file: properties.xml
These two errors are symptoms of the install/upgrade script not finding specific files in the current installation directory or the directory being created newly.
Files corruptions during download/extraction/edits etc.
1. Rollback to the source version completely (file system and DB)
2. Start the source version and do a sanity check. Preferably also run the Time Slicing job to completion
3. Download and extract the ISO again
4. Make sure that files/folders are not misplaced before or during extraction
Another common issue with upgrade to version 15.7 is explained at: