I don't have access to any proper Linux workstation right now, but this looks like it could a problem with highmem support.
Do you have support for more than 1GB of physical RAM compiled in your kernel and does changing the option make a difference?
Yes, CONFIG_HIGHMEM4G=y was in .config (copied from .config that came with distro - my starting point). Reconfigured with no highmem support and it's fixed. Can now read and write packet-cds and files are viewable in both Linux and Win. I see Peter has provided a patch too. Thanks Arnd, I dread to think what you could crack if you did have access to a Linux workstation! --- This message has been virus checked by Grisoft AVG during dispatch. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.332 / Virus Database: 186 - Release Date: 06/03/02