This happens when the drive, which contains the database file (DataBox.GDB) is not shared as a single letter coinciding with the logical device letter. This is a requirement of the Interbase engine.
Make sure that the drive, which contains the database file (DataBox.GDB) is shared as a single letter coinciding with the logical device letter. For example, if the database file is on C:\ProgramFiles\DMT\DataBox, the share name of this drive should be "c". Then, the remote station will find the database.