I think it may be questionable to put blame for Einstein's errors on his spiritual views while not giving credit as well for the hypotheses that panned out... how do you separate it out?
Einstein said: "Everyone who is seriously involved in the pursuit of science becomes convinced that a spirit is manifest in the laws of nature -- a spirit vastly superior to that of man."
It seems to me that E. may have believed that the universe is permeated by intelligence. Whether he was strictly speaking a panteist, I am not sure. Maybe our notion of pantheism is closest to what he believed... I never could decipher Spinoza.