Hi Christian,
Second question: What's the "best practice" for bulk imports while retaining the directory structure of the imported files using collections?
If you create a new database, you can use the CREATE command or db:create and specify a directory as initial input. The existing file hierarchy will be mirrored in the resulting database.
it seems i'm not quite used with the lightweight concept of databases in BaseX :-) - since it's very easy to create and use multiple databases, filling the db initially is a good and reasonable solution.
Regarding the server installation: i'm not sure what went wrong yesterday - anyway, i've ended up with another basex subdirectory in the home directory of my baseX user, containing an empty webapp directory - thus there was no DBA web interface and no logs to consult... but now (esp. after i've found the extremely valuable information about config files: https://docs.basex.org/wiki/Configuration) everything works smooth and nice.
Thanks again for your help! Florian