As far as grammar is concerned, there are no errors in your composition.

Literal

Grammar [about-に] concerning as-far-as, your composition [location-に] [topic-は] errors [topic-は] there-are-not.

~に関する限り is a formal set phrase meaning 'as far as X is concerned.' It scopes the statement to a particular domain. 誤りはありません uses polite negative to state the absence of errors.