Hard for me to say -- I would really need to see the notes to comment precisely. However:
- Entered In Error: They searched my details, and found an error. I too, have an "entered in error" -- and I have lived in Ontario my whole life! This is an innocuous message. They are just justifying the change to the record.
- Section 15 -- was this an Access to Information or Privacy Act request? If it was ATIA, then it makes sense, if you had some kind of military service record, or something similar. If it's a PA, then Section 15 only talks about making a request (Extension of limits).
- Gap in address -- that's bad. That + your family history forms the basis of your immigration file. Seeing them together isn't a problem -- but noting the issue, they may demand both again.
That's the best I can do without seeing it.