a) Welcome to the forum
b) You will get better help if you post in the section for the product you're using - Painter, Designer, etc.
c) You will get better help if your "Subject" introduces what problem you are having
d) The error might be because you did not "unwrap" your model in your 3D application prior to exporting the OBJ file - I cannot remember if that is the error or not, but it is a common oversight for new people.
