AppleScript Error 10810

Question

How do I fix the following?
root# /usr/bin/osascript /Users/me/Documents/balance_volume.scpt
/Users/josh/Documents/balance_volume2.scpt: execution error: An error of type -10810 has occurred. (-10810)
My iMac volume balance constantly sets itself to a new random position so I created the following AppleScript:
tell application "System Preferences"
    activate
    set current pane to pane "com.apple.preference.sound"
    reveal (first anchor of current pane whose name is "output")
end tell
tell application "System Events"
    launch
    tell process "System Preferences" to tell slider 1 of group 1 of tab group 1 of window 1 to set value to 0.5 --center balance
    -- tell process "System Preferences" to set value of slider 1 of group 1 of window "Sound" to 0 --maximize volume
    quit application "System Preferences"
end tell
The script works everytime when run from AppleScript Editor.  But if I save and try to run from the command line, it runs sometimes, but not others.  Eventually I want to put in crontab:
* 20 * * * /usr/bin/osascript /Users/me/Documents/balance_volume.scpt
I've read about "compiling" or saving as an application the scpt file but not sure how to do this.
Thank you.

Answer 1

Then I would try a minimalist version of the script. Who knows?
tell application "System Preferences"
    reveal (anchor 1 of pane "com.apple.preference.sound" whose name is "output")
    tell application "System Events" to tell process "System Preferences" to tell slider 1 of group 1 of tab group 1 of window 1 to set value to 0.5 --center balance
    quit
end tell