The question I need help with says "rewrite the following sentences, correcting errors in sequence of verb tenses" and the problem I have is : "Dr. King discussed the three ways in which people dealt with oppression in the past." I don't see anything wrong with this statement. Thank you for your help!

I don't see anything wrong with it either.

http://www.uottawa.ca/academic/arts/writcent/hypergrammar/vbseq.html

http://grammar.ccc.commnet.edu/grammar/verbs.htm
Scroll down to find the section on Sequence of Tenses.

To identify errors in the sequence of verb tenses, we need to look for inconsistencies in the timing of the actions or events being described. In the given statement, "Dr. King discussed the three ways in which people dealt with oppression in the past," there doesn't appear to be an error in the sequence of verb tenses.

However, to provide an alternative rewrite, we can change the sentence to a more present form:
"Dr. King discusses the three ways in which people deal with oppression."

By using the present tense throughout the sentence, we maintain consistency and keep the time frame in present tense.