The project administrator is an individual whose main role is to alleviate some of the routine tasks of the project manager and to help him with this daily activities.
Responsibilities include:
- Helping the project manager with the creation of the project management documents
- Helping with the updates of the different PM documents (especially the project schedule)
- Preparing status reports
- Doing other activities as instructed by the project manager
Note that quite often, the Project Team Leader assumes the role of the Project Administrator (that's why the companies that have this position are rare).