Toshiba D-R4SU

I have a Toshiba D-R4SU DVD video recorder. I have been trying to take my home movies from their VHS tape and record them onto DVD. I can do it onto a Memorex DVD-R, but I can’t finalize it. I’ve seen on this site that other people have had trouble with Memorex DVD’s and this machine. Today I tried a Sony DVD+R and I can’t get the machine to do anything with that. What else can I try and where can I learn more about this. Thanks in advance.