A multitude of adaptive computer-based training systems have been implemented in the last years. Whereas several aspects of these systems necessarily are dependent on the application domain, including the learning style and the system type, some other parts of the systems are very similar: usually they require an execution component, which steers and controls the interaction between the learner and the underlying data of the application domain, e.g. databases. For reusing purposes we have developed a highly flexible and adaptable domain independent execution system that allows the realization of different learning strategies in a web-based scenario. In addition to steering the interaction between learner and data, the execution system is enriched with model checking facilities. They provide a verification mechanism for learning material and thus can be used to support the authors. The described system is integrated into the web- and case-based project "Docs ?N Drugs".