...the plot thickens...
I have found a couple of DVDs that (almost) work. My Underground Resistance disc shows up but all the filenames have been truncated to old DOS names, though the tunes play.
My Sonic Youth disc contains audio files of all formats, .mov's, .pdf's, etc. Most of the files are neatly organised into dirs, apart from approx 50 'odds n sods' which are at the root. 10 files show up. Apparently there is only 59MB on the disc. My standalone DVD player shows all the files as they should be and I imagine Windows still does too (it did last week - but i deleted XP yesterday - something I'm beginning to regret!!!)
I burnt every disc I have in Nero using the same settings (inc. long filenames).
Here is what 'mount' shows:
/dev/ide/host0/bus0/target0/lun0/part1 on / type ext3 (rw,noatime)
none on /proc type proc (rw)
none on /proc/bus/usb type usbfs (rw)
none on /dev type devfs (rw)
none on /sys type sysfs (rw)
none on /dev/pts type devpts (rw,mode=0620)
/dev/ide/host0/bus0/target0/lun0/part6 on /home type ext3 (rw,noatime)
none on /mnt/floppy type supermount (rw,sync,dev=/dev/fd0,fs=ext2:vfat,--,umask=0,iocharset=utf8)
/dev/ide/host0/bus1/target0/lun0/cd on /mnt/cdrom type iso9660 (ro,noexec,nosuid,nodev,user=x)
The fact that there are helpful people out there stopped me from giving up Linux for once and for ever...