Thanks for sharing these errors. They seem to be caused by the CRUD generator not handling very well the peculiar structure of your domain object "asp net user logins", where the object consists entirely of the primary key fields, with no non-key fields.
So, for example, the standard Read operation takes by default the primary key fields, and returns other non-key fields (since you already have the keys, so no need to return those). In your case, the object has no non-key fields, so the output structure becomes empty, which is not valid in the Xomega model. Hence the error informing you that structures should either have nested <param> or <struct> elements, or reference another structure that is defined in the model (e.g. <output struct="my output structure"/>).
In your case, the entire Read operation seems to be quite odd, since you need to have the values of all the object's fields prior to calling it, as they are all part of the primary key. So there are no other fields to return there. The only point of the Read operation would then be to check if the specified user exists, i.e. throw an error if the provided user values are not in the DB.
That being said, I would advise to just delete any extraneous empty structures that were added by the CRUD generator, or to add the necessary parameters to them, if they are not supposed to be empty.
On our end though, we'll see if we can improve the CRUD generator to handle such objects better (by not adding those empty structures in the first place).
Please let me know if this makes sense to you, or if you have any other questions.