Actually Ethel Pnansonics are pretty much guaranteed to support DVD-RAM as they were a major supporter of it.
I had a Panny DVD-RAM writer about 4 years ago but after a couple of years it stopped recognising the RAM disks - although curiously DVD-R was OK. I found that using a cleaning disk sorted it our a few times but in the end even that stopped working.
I did like the features that the Panasonic had so I replaced it with a Panasonic hard disk recorder which has been absolutely brilliant.
So I'd suggest using a cleaner but be prepared because you may be on borrowed time.
I think I got one at currys but you can get them on line like here:
http://www.pixmania.co.uk/uk/uk/88510/art/fell owes/cd-dvd-player-cleaning-di.html
or here:
http://www.amazon.co.uk/Hama-DVD-Laser-Cleanin g-Disc/dp/B00005UPDF