What does the E50 error code mean on a Zanussi TCE7276W tumble dryer?

The condensor dryer starts up OK, but after a few minutes stops, the door ejects and the E50 error code is seen on the screen. I would guess this either has something to do with air cooling, have cleared and cleaned all vents but as the code is not in the manual it would be good to know what this code is. Is is something I could repair or a service call out?
Thanks!