A working applescript fails when running via cron

Question

MacOs 10.8.2 I have 2 applescripts shown below. They are arranged in one shell script to run one after another by using osascript (just to simplify the example). Everything works fine when starting shell script form the console. However if the same script scheduled in crontab I get an error from the second script.(First run just fine)

STAR-RECORDING SCRIPT

tell application "QuickTime Player"
    activate
    new screen recording 1
    start document 1
end tell

STOP-RECORDING SCRIPT

tell application "QuickTime Player"
    activate
    document "Screen Recording" stop
end tell

THE SHELL SCRIPT

osascript start-recording.scpt
osascript stop-recording.scpt

Additional info

1. There is only one user loged in the system. Cronjob is executed for him as well. I can visually confirm that recording was started after first scipt is executed

2. The error is saying something like this: Quick time cant get document Screen recording. error -1728

3. the crontab row is

    10 18 * * * /Users/usr1/test.sh
   

   where test.sh is the script running both applescripts as shown above