There are a few approaches to resolving the seeming contradiction between women's exemption from the mitzva of talmud Torah and obligation to recite birchot Ha-Torah. (We explore them in more depth in a forthcoming article.)
One approach is to say women in fact have no obligation to recite birchot ha-Torah, and only recite the blessings voluntarily.
A second approach maintains that women recite birchot ha-Torah over the obligation to learn practical halacha.
A third approach relates to a distinction (discussed in Learning Torah I)between a Jew's overall relationship to Torah and the more narrowly defined mitzva of talmud Torah. According to this approach, birchot Ha-Torah are not recited over the mitzva of talmud Torah. They are made over Torah and the relationship to it as a whole, which applies to women.