Venapps are intended to work in conjunction with a model or models. It is important that the correct model is loaded when using a Venapp (there is a LOADMODEL command to make sure this happens). Normally, when developing a Venapp, you should create and refine the model in Vensim before you begin working on the Venapp itself. A Venapp can be run with different models or different versions of a given model. If you are doing this, you need to be sure that the variable names referenced in the Venapp are present in all the models.
