Re: Command to Specify a Space in Remote Directory Path in a .cmd file
That's for URL. But you want "script", right? So switch to "Script" tab, it will show you this syntax:
See also https://winscp.net/eng/docs/commandline#syntax
"put \\servername\sharename\*.txt ""/New Directory/"""
See also https://winscp.net/eng/docs/commandline#syntax