This bug has been opened on https://launchpad.net/distros/ubuntu/+source/nautilus-cd-burner/+bug/41682

"Description of the problem:
I have some flakey disks that I can only burn at double speed even though they are rated at 4 speed. Consequently in any cd burning program I use I have to ensure the speed is no higher than 2 in order to use them.

However when I try and use nautilus burn it myseriously is unable to blank or burn anything to these disks (and I can see the light on the drive flickering on and off as it does when the speed is too high). If I manually use cdrecord then I can both blank and burn at speed 2. I suspect nautilus-cdi-burner is quitely ignoring my setting of speed 2 and instead trying to go as fast as it can. This is not easy to check though because nautilus burn no longer shows meaningful diagnostics when it fails instead resigning itself to saying:
Error writing to disc
There was an error writing to the disc

Steps to reproduce:
1. Insert a rewritable CD that claims it can be burned to faster than it can at a speed our drive can cope with.
2. In nautilus go to Places -> CD/DVD Creator .
3. Drag a small file to be burned into the CD creator window and press write to disk.
4. Change the write speed to 2x.
5. Click on Write.
6. (If CD isn't blank click on the Erase Disk button in the window that appears)

Expected results:
All CD burning actions (erasing, writing of image) to happen at the slower speed.

Actual results:
All CD burning actions (erasing, writing of image) seemingly happen at the Maximum Possible speed.

Additional Informatin:
CD burning no longer gives enough detail on errors.
...
> Thanks for your bug. Could you get a debug log by changing the "/apps/nautilus-cd-burner/debug" gconf key and running nautilus-cd-burner from a command line? You should have the details of the cdrecord call by example
...
http://librarian.launchpad.net/2385744/nautilus-cd-burner-cdrecord.txt
Thanks for the tip (I would have never have found the gconf key). Here's the cdrecord output. The pertitinent part is this:
cdrecord blank stdout: Starting to write CD/DVD at speed 4 in real BLANK mode for single session.
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> It seems that the log only has the blank command, which uses the fast option, it's probably normal to not have any speed used for it. Could you copy the log for the CD record too?
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"it's probably normal to not have any speed used for it [the blank command]"

I beg to differ. If a CD can't be burned at a faster burn speed you can't blank it at a faster burn speed either. Believe me I've tried. The only way you can work around the problem is to fix the blank speed too (and in the past nautilus-cd-burner did this).

It turns out that it is impossible to get nautilus-cd-burner not to try and blank the cd before it tries to burn data to the disk. Even when the inserted disk is blank it tries to blank it anyway..."