The first error in the sentence is with pronoun reference.. "After jeff talked to his brother about the proyect, He went home".Type of error is the last part of the sentence, "He went home" but.. who? jeff or his brother?
The error in the second sentence is with the pronoun agreement.. "Every frugal shopper counts their coupons before they shop " Type of error is the last part written. " Their coupons" You can change their to ITS but most style guides recommend avoiding this construction. Instead, the best option would be to change the sentence.
The error in the third sentence is in the pronoun reference.. " Someone decide to leave their mess behind for others to clean up ". Type of error : "others" has not epecification of who is talking about
The error in the fourth sentence is in the pronoun reference.. " the crowd sat through two hours of rainy soccer. it ended in a tie " Type of error : "it" it doesn't refers to something clearly
The error in the fifth sentence is in the pronoun reference.. " Neither the smiths or Mr . Paulson remembered to purchase thei" Type of error : "thei" it is not refering to anything in especific