Hey Fernando, ''to bring (someone or something) to (someone's or something's) knees'' may have two different meanings, as follows: 1) ''to render a person or group submissive by weakening or defeating them. E.g.: ''The general believes that such an attack will bring the opposing troops to their knees.'' 2) ''to disrupt or halt a process or thing.'' E.g.: ''Many fear that all of these new regulations will bring the stock market to its knees.'' I may say that both meanings should fit your example quite perfectly as it conveys the idea that such errors of calculation made the situation so difficult that the person almost couldn't stand it and the process of work could have been disrupted. Hope that helps!!!

"Brought me to my knees" is an idiomatic expression that means something was really hard so much so that "you could not stand".

Ex. The situation was so difficult that it brought me to my knees.

In this situation it emphasizes how difficult or frustrating the situation was.