Stumbling at rear, making mistakes (6)
I believe the answer is:
errata
'mistakes' is the definition.
(an erratum is a mistake in a printed work)
'stumbling at rear' is the wordplay.
'stumbling' is an anagram indicator.
'at'+'rear'='atrear'
'atrear' anagrammed gives 'ERRATA'.
'making' is the link.
(Other definitions for errata that I've seen before include "Mistakes in printed proofs" , "Mistakes (Latin)" , "Text mistakes" , "Mistakes in printing or writing" , "Misprints in a book" .)