Cannot delete files from site - Error:

WinSCP cannot delete files on a Windows Server web site. I have tried different folders, reinstalled WinSCP, used newest version, tried background and foreground deleting to no avail.
The error is: Error moving file <my_file.ext> to '/tmp/<my_file.ext'
The system cannot find the path specified.
Any ideas would be appreciated.

It seems that you have inadvertently enabled remote recycle bin. Turn it off.
https://winscp.net/eng/docs/ui_login_recycle_bin