Donation perhaps left in error (7)
I believe the answer is:
handout
'donation' is the definition.
(a handout is donated or given away)
'perhaps left in error' is the wordplay.
'perhaps left' becomes 'hand' (left hand).
'in error' becomes 'out' (out can mean wrong or inaccurate).
'hand'+'out'='HANDOUT'
(Other definitions for handout that I've seen before include "charity" , "dole?" , "financial support" , "Publicity" , "Donation" .)