The people that are actually doing the work need to be interviewed thoroughly to understand what they're currently doing and why they are doing what they're doing. There are a lot of intricacies that are involved in every business process. Some of the business processes that are in place may not make much sense, but it may be derived from years and years of history. Some of this history may predate your time within the company.
The management of the company needs to be interviewed, because we need to understand what they would consider a success to this system implementation project. Without understanding what the management wants from you as an IT manager, you can pour your heart out and work your fingers to the bones; the project may still be deemed a failure because the objectives of the management were not reached. Make sure to get their objectives in writing!
The goal of the analysis is not for you to solve the problems within the company. The goal...