I can even buy the excuse that the Septuagint became a "popular error" among the Jews of Palestine in the 1st century AD, but the Apostles were guided by the Holy Spirit. Asserting they used false or deficient Scripture denies their inspiration and authority.
Well, if it was inspired scripture, then why didn't they use it in all cases. I found Blogger's 11,196 (along with the full linked article) very helpful in answering questions like these. Again, it's not a matter of declaring the Septuagint to be all error, just that it is not inerrant, thus disqualifying it from being scripture. It is reasonable to assume that when the Apostles saw clear error they did not quote from it.