Random House unabridged:
'on the wrong tack' - under a misapprehension; in error; astray
(2)tack - 2a: the direction of a ship with respect to the trim of her sails <starboard tack> ... e: a course or method of action; especially: one sharply divergent from that previously followed
"This phrase was originally 'on the right tack,' 'tack' being a nautical term ...
" 'On the right tack' came to be applied to 'the course of a ship in relation to the direction of the wind and the position of her sails', and that is the sense in 'on the right tack': 'on the right course'. Apparently, speakers began to confuse 'tack', with which they weren't very familiar in that sense, with 'track', which seemed to make perfect sense (sort of like folks who call the television series 'Star Track' when it is actually called 'Star Trek').
" 'On the right track' dates from 1886, while 'on the right tack' dates from the late 17th century."http://www.takeourword.com/Issue092.html
One bilingual dictionary entry is a helpful piece of evidence, if not sufficient proof of modern usage. (We've all seen dictionary bloopers.) But in this case, other dictionaries and commentators agree with Oxford-Duden. 'Track' was originally a variant of 'tack,' but since it makes equally good sense and has been around for so long, both versions are equally valid.
Oliver and Corinna are probably right that 'track' is considerably more common, at least in AE. In my experience 'tack' tends to appear more in phrases like 'take the wrong tack / a new tack' or 'change (one's) tack.'
I support leaving both LEO entries unchanged.