Reads CDs but not DVDs only DVD Rams


I have a Windows 2000 system with a Toshiba SD-W2002 Dvd RAM fitted, this is on the second ide channel and set as master. There is also a Ricoh MP7040A fiitted as slave also on the second ide channel.

I can write to the DVD-ram with the Instantwrite 3.0 or Instantbackup supplied with the player but written by VOB.
When I try to read a DVD of any kind other than a DVD ram it returns a message box.

E:\ is not accessible

Invalid access to memory location.

I have checked all the settings and tried playing CDs without problem and a dvd ram cartridge can be seen and read, but no other DVDs.
The cd on the same ide channel had DMA settings and the DVD Ram was at PIO, the only difference I could find so set them both as DMA.
Checked your web site and found a untility with the drivers on so tried this.

But still the same, can any one suggest a way to get ordinary DVDs to play on the system.

I know they are a bit old now but the DVD Ram is a spare new one I had and I would like to get it working properly.