This paper explores how teachers with different teaching styles conceptualized and implemented a multimedia-supported problem-based inquiry (PBI) unit. We focus on how the teachers supported student thinking and examine underlying belief, knowledge, and dispositional factors that may account for differences in the teachers' practices. We hypothesize that certain dispositions and epistemological assumptions about knowledge may be prerequisites for effective problem-based practice. However, teachers who demonstrate those prerequisites may differ in other assumptions about students and what constitutes legitimate, feasible PBI. Those differences may lead them to different configurations of PBI practice that may produce substantially different outcomes. (Contains 3 tables.)