want to increase sound volume

My sound card is an nVidia MCP55 card which is not supported by ALSA. Jaunty installed sound kernel modules snd-hda-intel. The sound is not good and stutters at times but the main problem is that the volume is too low. I tried Steven Danna's suggestions in post #70666 from 2009-05-10 and followed his instructions.

1) Open a terminal (Applications->Accessories->Terminal)
2) Run the following command: mkdir ~/bin
3) cd ~/bin
4) gedit volume-adjust.sh
5) copy the following information into gedit:

#!/bin/sh

. /lib/lsb/init-functions
AMIXER="/usr/bin/amixer"
VOLUME="50%"
test -x $AMIXER || exit 1

case $1 in

    start)
        log_daemon_msg "Adjusting Volume" "volume-adjust"
        $AMIXER -c 0 sset Master,0 $VOLUME > /dev/null
        log_end_msg $?
        ;;

      *)
        log_success_msg "Usage: /etc/init.d/fancontrol {start|stop|restart|force-reload}"
        exit 1
        ;;
esac

exit 0

6) Save the file and close gedit.
7) Run the following command in the terminal: chmod +x volume-adjust.sh
8) Run the following command in the terminal: ./volume-adjust.sh start
9) Ensure that running the script adjusts the volume and that no errors are echoed to the terminal.

 After following his instructions I got an error report:
howard@howard-desktop:~/bin$ ./volume-adjust.sh start
 * Adjusting Volume volume-adjust [ OK ]
exit: 22: Illegal number: 0chmmmm
and the volume was further decreased rather than increased.
Any suggestions?