What causes GDM-36 errors when opening or working on a model?
GDM errors basically mean 'General Data Modeling' engine. Erwin run's thousands of modeling rules when it opens or converts a model. So one or more of the rules failed. Due to the complexity, the specific rules are not all documented, and the errors tend to be generic, but for the most part, are all related to some form of corruption in the model.
However, the GDM-36 error varies a little compared to the others such as GDM-46, GDM-129 and GDM-1001. The GDM-36 error is due to udp related corruption in the model, which occurs when the property type of the udp did not set to the type it is trying to set. check udp on the model and fix the data model