It seems you have been thrown into cold water without any guideance at all. To tackle this problem, I'd advise you to
- Install OpenACS for yourself (fresh install)
- Read the developer documentation
- Get some training from the persons who have written the previous OpenACS packages that you talk about.
- Attend a training session on OpenACS if one becomes available again or find an organization to sponsor a training session (read: hire someone to teach OpenACS).
- Contact a professional to help you out if the data is crucial and you don't want to loose it.
Retrieving the password and login of the admin or at least resetting it, is easily done, if SSH access is granted to a professional (who charges for this). But if you have no experience with the internals of OpenACS, it will cost more to try and solve this on your own.
Furthermore, if you want to upgrade OpenACS, this is not an easy step as well, depending on where you are coming from. Especially if someone made custom development on your site, and you have no clue what has been done / changed.
