kde here, this is my output of the same command, /usr/sbin is set up from
/etc/profile/kde4env.sh which clearly it's not installed in your system.
/etc/profile.d/10lang.csh: set consoletype=`/sbin/consoletype stdout`
/etc/profile.d/10lang.csh: if { /sbin/consoletype fg } then
/etc/profile.d/10lang.csh: if { /sbin/consoletype fg } then
/etc/profile.d/10lang.sh: consoletype=$(/sbin/consoletype stdout)
/etc/profile.d/10lang.sh: if [ -x /bin/unicode_start ] && /sbin/consoletype fg ; then
/etc/profile.d/10lang.sh: [ -x /bin/unicode_stop ] && /sbin/consoletype fg && /bin/unicode_stop
/etc/profile.d/kde4env.sh: PATH=/usr/bin:/usr/sbin:/usr/lib/kde4/libexec:/bin:/sbin:/usr/X11R6/bin:/usr/games:/usr/local/bin:/usr/local/sbin
/etc/profile.d/kde4env.sh: PATH=$PATH:/usr/bin:/usr/sbin:/usr/lib/kde4/libexec:/bin:/sbin:/usr/X11R6/bin:/usr/games:/usr/local/bin:/usr/local/sbin
To fix your problem on the fly, try the following:
PATH=$PATH:/usr/bin:/sbin
export PATH
mylivecd test.iso
On the long run further investigation is needed to understand if the problem is related only to your system or not ...
AS