FreeFTPD is the best recommendation on a SFTP server to use to back up CUCM. I have also experienced on similar problems with the FreeFTPd tool as SFTP what you are facing now. The way I have configured it is as follows:-
1. Under SFTP configure the SFTP root directory for example E:
2. Create your user and configure the home directory E:\Backup
3. Under virtual directories create a folder named Backup, set the virtual to Backup and configure the real path to E:\Backup
4. When you configure the DRS network location specify / for the path name.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.