<em>The first error in the sentence is with pronoun reference.. "After jeff talked to his brother about the proyect, </em><em><u>He</u></em><em> went home"</em>.Type of error is the last part of the sentence, "<em><u>He</u></em> 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.
<em>The error in the third sentence is in the pronoun reference.. </em>" Someone decide to leave their mess behind for <u>others</u> to clean up ". Type of error : "others" has not epecification of who is talking about
<em>The error in the fourth sentence is in the pronoun reference..</em> " the crowd sat through two hours of rainy soccer. <u>it</u> ended in a tie " Type of error : "it" it doesn't refers to something clearly
<em>The error in the fifth sentence is in the pronoun reference..</em> " Neither the smiths or Mr . Paulson remembered to purchase <u>thei</u>" Type of error : "thei" it is not refering to anything in especific