Darn! Accepting credit leading to ruin (5,2)
I believe the answer is:
screw up
'ruin' is the definition.
(I've seen this before)
'darn accepting credit leading' is the wordplay.
'darn' becomes 'sew' (I've seen this in another clue).
'accepting' indicates putting letters inside (inserted letters are accepted).
'credit' becomes 'cr' (abbreviation).
'leading' becomes 'up' (similar in meaning).
'sew' going around 'cr' is 'screw'.
'screw'+'up'='SCREW-UP'
'to' is the link.
(Other definitions for screw up that I've seen before include "Ineptly fail" , "Make a mess of things" , "Go badly wrong" , "Summon" , "Get it badly wrong" .)