Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ŏpĭtŭlātus, ūs, m. [opitulor], a helping, help, aid (post-class.): ejus opitulatu, Fulg. Myth. 3, 8.
ŏpĭtŭlor, ātus, 1 (old inf. pres. opitularier; v. in the foll.), v. dep. n. [ops-tulo, whence tuli], to bring aid; to help, aid, assist, succor (class.; syn.: adjuvo, subvenio, auxilior, succurro): amanti ire opitulatum, Plaut. Mil. 3, 1, 27: amicum amico opitularier, id. Curc. 2, 3, 54: sontibus, Cic. Fam. 4, 13, 3: inopiae, to relieve, Sall. C. 33, 2: permultum ad dicendum, Cic. Inv. 2, 2, 7: frequentatio, quae conjecturalibus causis opitulatur, Auct. Her. 4, 40, 53.