I object, return, finish at the final 500; removed errors (9)

'removed errors' is the definition.
(with errors corrected)

'i object return finish at the final 500' is the wordplay.
'i object' becomes 'me'.
'return' says the letters should be written in reverse.
'finish' becomes 'end' (synonyms).
'final' says to take the final letters.
'500' becomes 'D' (Roman numeral for 500).
The final letter of 'the' is 'e'.
'me' reversed gives 'em'.
'em'+'end'+'at'+'e'+'d'='EMENDATED'