Which version of the firmware are you now using (v.......23) is the latest.
Many many people had problems at DSO and you should take a look at click here which is a dedicated sub-forum for Humax PVR's.
I had a similar problem after DSO and found I had other versions of BBC1 etc in the 8xx slots in the channel lists. Humax PVR's seem very sensitive to duplicated channel in the 8xx slots and I had to retune manually to remove these after a factory reset.
Good luck. Humax aren't very good on helping customers so you may find the above forum more helpful.