Getting an error whenever I use DB_DataObject::joinAdd()

Hi, I recently upgraded my DB_DataObject from a pre v1.80 to v1.82. On two sites I now get a fatal error when I call DB_DataObject::joinAdd(): *DataObject_MusicArtist: databaseStructure:* Cant find database schema: gyford_phil/phil_music_artist in links file data: Array ( ) *DataObject_MusicArtist: ERROR:* Unable to load schema for database and table (turn debugging up to 5 for full error message) I can't see why this is... joinAdd() ends up calling DB_DataObject::databaseStructure() and it seems like the database structure can't be found/created for this object, which is odd when it works fine for all other, non-joined objects. I'm using a database.links.ini file but not a database.ini file - the structures are defined in the objects themselves. If I just stick in "return true;" after line 1779 ("- if not try building it..") then the site works as expected. Obviously, this isn't a solution, but I can't see what I've done wrong that is causing it to fall over at this point. I'm not sure what else to say that could help someone help me - do ask if I can provide further information that would be useful. Many thanks, Phil