An information processing system including at least one terminal and at least one program execution apparatus. Each terminal transmits a message containing version information indicating a program version to a program execution apparatus. Each program execution apparatus stores one or more program components, and holds in a pre-transfer information management table information on the program components. Each program execution apparatus includes a memory allocated to an activated process and temporarily storing at least one program component for execution; and also includes a post-transfer information management table holding information one or more program components. When each program execution apparatus receives from a terminal a message containing version information, a program executing unit in the program execution apparatus dynamically links one of the program components and corresponding to version information in the received message, to the memory, enabling execution of the program components in the process.