All I could say about that is that there is an error in the macro that executes when a document is created. Why it fails I cannot say. You need to debug the macro I guess, for example by using message boxes here and there to see how far the macro runs without an error.

Thank you for your answer @Mathias Dahl I am going to try to follow your suggestion and see what happens.

If you don’t need macros you can always disable them for the document class you are using. It can be done under Document Class Process Action.

The solution found was indeed to go in Document Class Process Action and change Document Process CREATENEW with Macro Option NoMacro.

Thank you @Mathias Dahl 

Someone wanted that macro to be used though... But perhaps this was not a production environment...