"Cactus" .... is a particularly australian slang for something that is 'NQR' (not quite right) usually involves being bent in shape with sticking out sharp bits.
"FKD" ... is another technical term meaning 'not now working at all'.
quite often used with the word "up" following, I.E. Ar*e UP.
and can often be used with the word, "Properly" preceeding, when it's real serious.
but then to twist this one a bit,
Thus a "cactus chopper" is an unserviceable helicopter
may well be what we call a prickly d*ck.
cheers tet