It is needed to create a PVA user with limited privileges and provide him the ability to create scheduled tasks. But there's no special permission that covers Scheduler, and it is only available to users with full privileges.
The issue is recognized as a PVA product bug with internal ID PVA-33894.
A special permission, devoted to Scheduler, is planned to be included into PVA security schema in one of the next PVA updates.
For now, Scheduler can only be used by PVA users with full administrative privileges.