Comment 2 for bug 451420

I have found that the problem is related to DMA. I read some info in other places about this. His is a work around (but causes another problem I'll explain in a moment.

add "options pata_ali atapi_dma=1" to /etc/modprobe.d/options (new file)
add "echo 1 > /sys/module/pata_ali/parameters/atapi_dma" to /etc/rc.local
add "pata_ali atapi_dma=1" to "/etc/initramfs-tools/modules"

The problem is with DMA enabled, any time I do any kind of disk intensive operation (ie. copy a large amount of files from one partition to another.) I cannot do anything else until the operation is done as the system becomes unresponsive. But it does seem to resolve the issue although I have only burned one DVD since finding this issue. As a work around I can run:

echo 1 > /sys/module/pata_ali/parameters/atapi_dma and then echo 0 after. Perhaps that would be something to consider from within Brasero? Or perhaps there is a way to only enable DMA on the DVD and not the HD? I'm out of my league on this so just random thoughts.

As far as trying in Karmic, unfortunately, I'm not in a position to do that until it is production ready as my machine is in constant production use.