Database in this case means the collection of Component and Descriptor definitions (plus some other stuff) that is being used by ArchiCAD's Calculation functions.
These databases can be defined in GDL, too.
Any file in your loaded Libraries that start with "MASTER_..." and end with ...GDL" will be executed whenever you load or reload your libraries.
There is a line in that MASTER GDL file which defines a DATABASE.
But it seems that there are more than one of these MASTER GDL files in your loaded libraries and 2 of them trying to create databases with the same name.
So as the easiest solution I would remove one of them from my loaded libraries, because the other solution would be to start editing the GDL code of those files and I don't know if that would be a good idea.
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