Why can I not change channel on my Satellite receiver?

Have a SatMax A1600 Satellite receiver with the channel change stuck on the number 0800 and channel change Up & Down will not change it. Looked in Menu & Parental Control and found Channel Lock -----On. On the Parental Page is "Input Password" -"-Menu Lock"-- "Channel Lock" "New Password" &" Confirm Password. As receiver was bought 2nd hand I do not have the passwords and the manual for the receiver states the default Password for "Input password" is 00000 but this does not open it for me to get at the into the other functions. The manual also states If you change or forget the password then the receiver will need new software to gain access. Does anyone know how I can gain access to this software. Would be gratefull for any help with this problem. Cheers Fred