Vertices contain 3 information (which are the different vectors) : the normal, the tangent, the bitangent (or sometimes also called binormal). If the normal is valid, Substance Painter is able to recompute the two other vectors.
If an error appear in the log when you import the mesh, that means the value/data store din the file is not valid for Substance Painter. Unfortunately it is hard to tell why or what is the source of the problem because this is completely dependent of how the source application (3D Software) generated the mesh file in the first place.
You will have to investigate on your side which part of the mesh is invalid for example and see if you can fix it/clean it.
