There are no errors in the statement: “Ramesh is wearing a new dress, isn't he?”
Explanation:
The sentence is in the present continuous tense and is grammatically correct. "Ramesh" is the subject of the sentence, "is wearing" is the verb phrase in the present continuous tense, and "a new dress" is the direct object of the verb. The tag question at the end of the sentence uses the contraction "isn't he?", which is a correct way to form a tag question in English.
Also, the use of "isn't he?" at the end of the sentence is appropriate because the subject of the statement is singular ("Ramesh") and male, and "isn't he" is a common tag question used to confirm or seek agreement on a statement about a male subject.