Missing or invalid absolute path on FTP server

Hello,
i’ve ran into a little situation that took me a while to resolve.
I’m trying to add a scheduled back up in webmin (virtualmin 3.94 gpl).
I managed to make it work with virtualmin but when i try to add a FTP server in webmin i get the following:
“Missing or invalid absolute path on FTP server”

I tried the following for the input field “file on server”:

srv-bu/server15

then, in contrary to the virtualmin settings, this worked:

/srv-bu/server15

…but then i got:

STOR /srv-bu/server15 failed : /srv-bu/server15: Not a regular file

… so, finally i tried:

/srv-bu/server15/file

…and it works.

It would be nice if there was a way to add the server and its settings first and then try if the connection works.

It would also be nice to append a little hint to the input field like “/some-dir/backup” to make this more clear.

Thanks for a great product!