A computer system has a main system to execute an application in cooperation with a human user. The auxiliary system evaluates problems in the main system. The auxiliary system has a service module to collect problem related data from the main system, an acquisition module to acquire knowledge representations, a knowledge module to store knowledge representations, an inference module for processing problem related data with knowledge representations to identify solutions and for forwarding the solutions through the service module to the main system. The main system has a client/server configuration with a database, an application server, and a front-end-server. The auxiliary system uses basis functions of the main system.