Heya all, I've just joined the forums and saw this guide with the question about starting on server reboot..
Try this, but change the launch.sh path if required:
echo '#!/bin/sh -e' > /etc/rc0.d/StartTekkit
echo '/srv/tekkit/launch.sh' >> /etc/rc0.d/StartTekkit
echo '#!/bin/sh -e' > /etc/rc1.d/StartTekkit
echo '/srv/tekkit/launch.sh' >> /etc/rc1.d/StartTekkit
echo '#!/bin/sh -e' > /etc/rc2.d/StartTekkit
echo '/srv/tekkit/launch.sh' >> /etc/rc2.d/StartTekkit
echo '#!/bin/sh -e' > /etc/rc3.d/StartTekkit
echo '/srv/tekkit/launch.sh' >> /etc/rc3.d/StartTekkit
echo '#!/bin/sh -e' > /etc/rc4.d/StartTekkit
echo '/srv/tekkit/launch.sh' >> /etc/rc4.d/StartTekkit
echo '#!/bin/sh -e' > /etc/rc5.d/StartTekkit
echo '/srv/tekkit/launch.sh' >> /etc/rc5.d/StartTekkit