The images in your first post here didn't come through, but it sounds like you're referring to using angle brackets in file/folder paths via the Dropbox web site versus the Dropbox API.
The Dropbox web site is a bit more restrictive than the API in this regard, e.g., since angle brackets are reserved on Windows. You can find more information on these restrictions here:
https://www.dropbox.com/help/145
You may wish to have your app enforce this restrictions when using the API depending on the use case for your app.
in effect i can't via dropbox.com account interface ... but i can with remote script. Is ok?
ah so nice ... this the reason ...Thank you as ever to point me to what i had completely ignored