I have just uploaded an update to the Scheduled Task Management Pack. Under certain circumstances the discovery of Windows 2003 tasks failed. The new version 126.96.36.199 fixes the bug in the discovery script.
I do recommend everyone who is currently using version 188.8.131.52 to upgrade to 184.108.40.206. Simply download the new version here and update the management pack by importing Custom.Windows.TaskScheduler.Windows2003.Monitoring.mp.
Many thanks to Aengus and Mark for making me aware of this bug.