This is a duplicate of #4291. It'll be fixed in the next release.

This screen snapshot demonstrates that the “duplicate error” occurs when the class names and declared package names match even if the source file exists in directories with different names ...

It's hard to tell what is wrong without seeing the whole entity or what you are doing with the entity. On a first glance, you can not create index in NitriteId field. This field is to retrieve the ...