Like any IT project, the intricacy of Enterprise Resource Planning (ERP) implementations brings with it high risks to the organization because of high upfront costs and low success rates. ERP implementations are not simply software installations but a radical integration and transformation of an organization's business practices. System acceptance and perceptions of success weight heavily on non-technical forces such as people, processes, policies, and organizational culture. This study employs system dynamics techniques to elicit perceptions regarding system acceptance and success in an ERP post-implementation case study setting. A conceptual model was developed based on various literature streams and structure validation was conducted with ERP experts via semi-structured interviews. The resulting model includes technology acceptance and information system success model concepts as well as theories from related literature. Interview findings and methodology reflections are also discussed in this paper.