I'd need more information. What kind of task (batch, start/stop service etc.)? Is the task set to run under the admin user/password? Are policy settings set to allow the user to do the function of the task?
Under user manager,Policies, user rights, if it is a batch, there may be a policy setting that needs changed (log on as a batch job, or act as part of the OS more specifically)(it depends on exactly what you are trying to do).
(hehe, good one BK!😀)