launchctl load call (made via applescript) hangs

My app wants to submit jobs to launchd for scheduling. If you use Script Editor to attempt…

do shell script “launchctl load ~/Library/LaunchAgents/myJob.plist”

…you can expect a 30 second delay (the same command runs near-instantly in the terminal). If you make this call within an Applescript STUDIO application, it appears to hang indefinitely.

Can anyone advise either a solution to overcome this problem directly, or suggest an alternative means of scheduling (not cron).

Thanks,

Dave.

(iBook G4, OS X 10.4.11)