Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
trībŭlātĭo, ōnis, f. [tribulo], distress, trouble, tribulation (eccl. Lat.), Tert. adv. Jud. 11; Aug. in Psa. 125, 2; Hier. Ep. 108, 18.