I think what the architect exactly said was that he was helped by others to create the matrix, and that IF there was a mother of the matrix it would undoubtedly be the Oracle. So he didn't exactly say that the Oracle had the title of the "mother of the matrix" but it was implied that she was at least very influencial in creating it.
What would have happened if he had gone through the other door?
****MORE SPOILERS, don't read if you don't wish to know****
Correct me if i'm wrong but the arcitect told him that if he went in the right door he would be allowed to choose 34 (?) people from the matrix and take them to rebuild Zion after the machines had destroyed it. This would then continue the cycle of anamolies and possibly give the humans a chance to destroy the matrix at a later date. This was ovbiously the choice they wanted him to take. The other door then being one that lead to the destriction of Zion and all of mandkind.