We've been here before with your connections - can you confirm that you have connected the lead from your aerial to the RF-in socket on the back of your DVD recorder and then the lead (supplied with the DVD recorder) from the DVD to the TV.
It is not necessary to program your DVD remote to operate your TV - just use the DVD remote to operate to DVD and the TV remote to operate the TV.
When you turn off the DVD recorder do you use the remote or do you switch off the power at the wall socket? - you only need to power off with the remote or the standby/off button on the front of the DVD recorder. That could be why you are losing your channels.
The recorder has a built-in hard disc - why are you attempting to record on a DVD disc? You must be doing that or the tray would not open.