Windows 2008 Task Scheduler – Other User unable to run the Task-Collection of common programming errors

I have created a scheduled Task in Windows 2008 Task Scheduler. (as a member of the local admin group). It runs on time and I can run the task anytime I want. However if a coworker tries to run the same task he can’t because insufficent permissions, but he is also member of the local admin group). Anybody having an idea what is wrong here ?