Page 1 of Aiwa HT-DV90 problems with dvd+rw and possibly dvd-r

I have just bought one of these from Currys (in the sales for £150 ex display).I seem to have a problem with it if I load a dvd+rw or DVD-R in it.
It seems to lock up and then after powercycling it will only display L+R front speaker icons and will only be in stereo . I cannot change the setting for surround at all - it is completely locked .The only way to get it back to normal is to powercycle it numerous times and hold the stop button in (hard reset ) many times . Has any one else experienced a media problem with this player in the same way ?
I know aiwa will probably say dvd+rw is not supported in it , but I would be a bit concerned if it cant play dvd-r

Many Thanks

Jim

I bought the same machine from makro has played dvd-r svcd vcd no problems at all