The CapBasED-AMS (Capability-based and Event-driven Activity Management System) is a workflow system developed in [5] deals with the management and execution of activities. A Problem Solving Agent (PSA) is a human, or a hardware system, or a software system having an ability to execute activities. An activity consists of multiple inter-dependent tasks that need to be coordinated, scheduled and executed by a set of PSAs. The activity execution is based on the occurrence of events. That is, a PSA after completion of a task (atomic activity) generates events, which are captured by the activity management system, for initiating the execution of the next task. In this paper, we describe three-tier system architecture to implement Web-based event-driven activity execution of CapBasED-AMS.