DVD will not mount

Hi Everybody
i'm from the UK and new here but not new to Macs

I'm a big Logic Pro User and just upgraded to Leopard. I tend to backup my data on DVD-R disks using Toast 9.

When I first write a disk it mounts ok, but when i eject and try to re-mount my G5 Mac won't recognize it and just spits it out.

This only happens when writing data disks to DVDs, CDs and Video DVDs are ok.

This has got me beat!!! worked ok before I upgraded to leopard.

Anybody got any ideas

Try another media brand. Also, if you're burning to DVD - R media, try DVD + R instead. Or, vice-versa.

Regards.

Hi

Thanks

Already tried 2 different brands and - and + R no luck!!
writes Ok but then won't show on the desktop!! but will mount on my PC laptop Hmmm
I'm wondering if my writer is on its way out!! it's 3 years old now and it's had a lot of use. But why will it show commercial stuff and CDs?DVDs i burned months ago but not any new stuff.
anybody technically inspired with any ideas!!

Robb