Cannot connect via SCP and command shell - via GUI it works

Hi

I have the problem that I cannot connect to a device via the command shell.

in windows i open a command shell

winscp ENTER
open 168.10.1.61@root
I enter the correct password and then I usually get an error message:

Connection has been unexpectedly closes ...... Exit Status 127

When I turn on the logging everything is OK except for following line:

Using SFTP protocol (how do i tell it should use SCP)
and then following error is written there:

sh: /usr/libexec/sftp-server: not found

Please help
THx

Br
Stefan

Please attach a full log file showing the problem both for GUI and scripting session (using the latest version of WinSCP).