Before using model files with the DLL program, they must be published as .vpm files. Graph files must be saved as .vgf files (from Graph Control in Vensim). The DLL version of Vensim cannot open .mdl or .vgd files, nor can it read the default graphs for a model.
When you install the DLLs two model files are installed for use with the examples. The DLLs install two models files:
WORLDAPP.VMF - The Word Dynamics model of Jay Forrester.
WORLDAPP.VGF - graph definitions for this model.
POPSUB.VMF - is a subscripted model that is used by some of the examples.
The model and graph definition are referenced by the examples and shouldn't be removed.