Motor & Canal Satellites: Any help

Hi Guys

I’m having some trouble with my dream box 7020 S (120 GB HD). The problem is related to the disecq motor.
In fact initially, I have searched and stored 16 satellites position in the motor. But recently it has not been possible to connect to 19.2 (Astra) for canal Satellites (French Channel). When I zap to canal satellites service, the motor will take infinity to rotate to 19.2 (canal Satellite on Astra) and the box will show the following message: “Service not found” and the screen is blank. If I turned to any channel of Digital Spain (Astra 19.2), the motor turned normally and I can view the channel.
The motor will find all the stored positions and display the services except for canal Satellites (French Channels).
Initially, I thought thet transponder has changed and when I searched for a better transponder in that satellites, I can find a better transponder, but I can’t saved it; when I saved the transponder, the dream box do not saved the new transponder and revert to the default transponder for Canal Satellites.
I wonder if this is related to my box or to the service provider do you know any way to solve this problem. I have posted it to some forums but haven’t got any answer yet. Will appreciate your help once again.

Many thanks for your time.