Hi,
as developer of libburn i advise to use the libburn backend of Brasero.
For burning of CD you could also tell Brasero to use wodim instead of
cdrecord.
Xfburn uses libburn unconditionally. So that would be another way to
avoid using cdrecord. More ways are: K3B with cdrskin as backend, or
using wodim+genisoimage, cdrskin+genisoimage, or xorriso from the
command line.
I understand from the shown mkisofs command that you plan to write a
data CD, not an audio CD (which would need no genisoimage and would not
be possible via xorriso).
If you want to continue using cdrecord, then you will either have to
run Brasero as superuser (darn dangerous) or set the properties of the
cdrecord program file to become superuser when it is run (still quite
dangerous).
For the property change, find out where the program is stored:
type cdrecordwhich should answer something like
cdrecord is hashed (/usr/bin/cdrecord)Determine the ownership of that file:
ls -l /usr/bin/cdrecordwhich should answer something like
-rwxr-xr-x 1 root root ... /usr/bin/cdrecordIf it is not yet owned by root, do as superuser or by sudo:
chown root /usr/bin/cdrecordWhen it belongs to the superuser, do the decisive (and dangerous) change
as superuser or by sudo (this is called “setting the setuid bit”):
chmod u+s /usr/bin/cdrecordAfterwards, ls -l should show a “s” where normally is the “x” for
“executable by the owner”:
-rwsr-xr-x 1 root root ... /usr/bin/cdrecordThis means that whoever is allowed to execute this program will be promoted
to superuser within this program run. cdrecord will be able to get a drive
error message from its probing command rather than a “Permission denied”
error. This should make it happy and willing to work.
But it also makes cdrecord unconditionally powerful and opens attack ways
for people who have underpriviledged access to your machine and want to be
superuser against your will.
Have a nice day 
Thomas