It is relatively safe for multiple people to simultaneously edit the same TntMPD database over the network. Special care is needed to avoid data corruption. Let me unpack this:
TntMPD uses a file-based database system (MS Jet/Access to be precise). If TntMPD's connection to the database file is interrupted during a write operation, there's a really good chance for failure. Even the most reliable network will never be as reliable as a local hard drive. And as more users simultaneously connect to the file, the chance of a single point (the one file) failure goes up as well. Network failures, power failures, and Windows not flushing the write-behind cache if you don't shut down properly (or eject the USB drive properly) are all possible types of failure.
In practice, however, failures like this happen very rarely. But they do happen enough that I added an auto-backup feature to TntMPD so that every time you close the program a local backup is created (or a backup is created to the place you specify in the options).
So the best ways to avoid data loss:
1. Maintain a reliable file sharing server and network.
2. Maintain regular backups.
3. Encourage users with a shared database open over the network to close TntMPD when they are done using it.
I use the shared database feature every day when I sync to my wife's computer (using TntSync), and I've never had a failure since 1998 when I started using it. :)