Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
auxĭlĭātor, ōris, m. [auxilior], a helper, assistant (post-Aug. and rare): litigantium, Quint. 12, 3, 2: haud inglorius, Tac. A. 6, 37: aegris auxiliator adest, Stat. S. 3, 4, 24: auxiliator tuus, Vulg. Deut. 33, 26: noster, ib. 2 Par. 32, 8: ejus, ib. Ezech. 30, 8 al.