ProPlan 5.2 could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. We recommend checking the downloaded files with any free antivirus. ProPlan relates to Photo & Graphics Tools. The actual developer of the free software is Ingenious Inc.
From the developer:
ProPlan is a production planning simulator. The product is an extremely powerful, yet user-friendly application that facilitates the optimization and planning of plant operations. An economic analysis together with flexible planning of products and or capacities may be conducted for the complete plant. ProPlan is OPC compliant and web enabled making it easy to access from anywhere in the world and integrate with third party applications.
You may want to check out more software, such as ProPlan CMF, which might be related to ProPlan.