alert subid XX points to non-existant class

Something on my NAV dashboard triggers errors in the apache error log: [wsgi:error] [WARNING] [pid=15075 nav.models.event] alert subid 5691 points to non-existant <class 'nav.models.manage.PowerSupplyOrFan'> [wsgi:error] [WARNING] [pid=15075 nav.models.event] alert subid 251536 points to non-existant <class 'nav.models.manage.NetboxEntity'> (I have omitted date and remote IP from the log lines) How can I debug this? --Ingeborg -- Ingeborg Østrem Hellemo -- ingeborg.hellemo@uit.no Dep. of Information Technology --- Univ. of Tromsø