Fixed empty author error in learning object OAI import

app/builders/learning_object_builder.rb

@@ -47,6 +47,7 @@ class LearningObjectBuilder
     lo.language = language
 
     lo.author = lo.get_metadata_values_of('dc.contributor.author').join(', ')
+    lo.author = publisher.name if lo.author.blank?
     lo.description = lo.get_metadata_value_of('dc.description')
 
     lo.state = LearningObject.states[:published]