What "usual probability multiplication error" are you referring to?
Its the error of assuming the probability of subsequent events happening is independant of the previous events. I assume this is what he is referring to. Its the old 'Boeing in Junkyard" argument. There are some good articles about it around and about. Try this one
...As a brief summary- Schneider sets up his ev program so that it cuts selection out of the picture. The result is no information increase (the actual result is 0.00e+00 +/- 4.66e-10). As soon as selection is introduced...information content increases. This would seem to indicate that selection is extraordinarily important.
Some time ago Dr Tom Schneider wrote the paper ‘Evolution of Biological Information', only to have it thoroughly refuted by Dr Royal Truman (link). In Schnieder’s response, he offered very little in defense other than an article he wrote for the internet 'The AND-Multiplication Error' (Dr. Schnieder’s excuse for his scant rebuttal was “I have other things to work on”! (see link).
Several evolutionists have latched on to this defense, essentially parroting Schneider without realizing the speciousness of the article.
It turns out the only defense Schneider offered is built on illusion. It is a strawman argument, followed by invalid assumptions on population genetics that have no support from even evolutionist journals!
Schneider writes “The multiplication rule does not apply to biological evolution”.
For starters, almost all of the protein chain calculations used by creationists are used to refute abiogenesis. Evolutionists love to point out time and time again how “evolution” is not abiogenesis! If we are to accept the evolutionists complaint and keep these two separate (IMO this an equivocation, but that’s another debate), then the evolutionist is forced to admit that Schnieder has erected a strawman!
He then writes: “We then find the card that has the most coins with heads up and we throw away all the other cards. So if even one card has an extra head, it will be found… That is what happens in nature.”
This is not true and easily disproved. This is called “truncation selection”, which doesn’t happen in nature! Aside from common sense, we can establish this using evolutionist’s own words from their journals  and from it’s absence from college textbooks. Truncation selection would be a powerful mechanism, but it only happens with man-made intervention like artificial selection (that’s the only time you’ll see it mentioned in the college biology books), or in programs like Dr. Schneider’s (thus one of many reasons his program is bogus). He tried to sneak it past us with the just-so statement “that is what happens in nature”, but there is not even the smallest shred of evidence this is true. It is an illusion masquerading as “science”.
To further enhance the illusion, he mentions the dandelion. The fact that a dandelion can maintain or increase it’s population rapidly due to huge numbers of progeny, has absolutely nothing to do with truncation selection! This was a remarkably short-sighted analogy by Schnieder, and I suspect evolutionists would have a hard time finding even one population geneticist to agree that this somehow supports truncation selection!
In summary, while it is true that the Multiplication Rule requires the events to be independent, Schnieder uses the argument as a strawman (if you accept the evolutionist terminology that differentiates between evolution and abiogenesis). He ends with amazingly naïve assumptions about population genetics that are not even remotely true, assumptions that have no support even from evolutionist literature.
 Schnieder applies extreme truncation selection. A less severe version of truncation selection is essentially called "synergistic epistasis", and even evidence for it is scant: “Although there is some theoretical support for synergistic epistasis (Szathmary 1993; Peck and Waxman 2000), there is little experimental support for this type of gene interaction (Willis 1993; Elena and Lenski 1997).” - Agrawal and Chasnov 2001. Also, “Current evidence is equivocal as to whether the required levels of epistasis exist.” - Siller 2001