Vista - Permissions Needed to Add a Task Using Task Scheduler 2.0

I am developing a component that uses the Task Scheduler 2.0 COM API
(via the managed wrapper available here: http://www.codeplex.com/taskscheduler
). The call to RegisterTaskDefinition works fine if I run the code as
a Domain Administrator. However this code is supposed to run under a
regular user. When I run the code as that user I get HRESULT
0x80070005 (E_ACCESSDENIED). I have searched through the local
security policy on my vista machine I can't find anything. I tried
giving the user in question read/write/delete access the corresponding
task folder in system32\Tasks\... I am not sure what else to do, but I
am certain I don't want to make this user an administrator!