In _Darwin's Black Box_ Behe admitted that his argument did not rule out indirect routes.
While I don't have the book to hand the quote can be found online in a number of places - on sites that agree with and sites that disagree with Behe.
"Even if a system is irreducibly complex (and thus cannot have been produced directly), however, one can not definitely rule out the possibility of an indirect, circuitous route. As the complexity of an interacting system increases, though, the likelihood of such an indirect route drops precipitously." (page 40)
(Taken from
Irreducible Complexity Demystified )
As I have stated Behe has never justified his claims concerning probability. They remain his personal opinion, and therefore his argument remains incomplete.
This paper looks at the possible routes (as general classifications)
http://www.cbs.dtu.dk/staff/dave/JTB.html
I beleive that you have misunderstood Perakh's comments, and that he is referring to "Irreducible Complexity" as the term is used in Algorithmic Theory of Probability (see
Talk Reason: arguments against creationism, intelligent design, and religious apologetics )