Humbert of Silva Candida was an important medieval theologian, best known for his involvement in the excommunication of the Patriarch of Constantinople in 1054.
He was also a vocal proponent of a number of views, such as papal authority and clerical celibacy. On this latter point, Everett Ferguson writes that he "said that sacraments administered by married clerics were invalid," and then continues:
Humbert's later work Against the Simoniacs in three books made a similar claim: Any cleric appointed to office by a layman, no matter how honestly, could not administer valid sacraments, a doctrine that revived the viewpoint of Donatism, which made the validity of sacraments depend on the status of the administrator. (Church History, I, 19.V.B)
This does sound like Donatism to me, but I don't see any indication on Wikipedia or elsewhere that Humbert's views actually violated Catholic dogma. In light of subsequent clarifications of the doctrines of the sacraments, are these views of Humbert's considered problematic in modern Catholicism?