Which error is present in this statement: "I have saw that movie before?"

The statement "I have saw that movie before" contains a grammatical error in the use of the verb "saw." The word "saw" is the simple past tense of "see," and it should not follow the present perfect auxiliary verb "have." In the present perfect tense, "have" is followed by the past participle form of the verb. The correct past participle of "see" is "seen." Therefore, the correct sentence should be "I have seen that movie before." This aligns with the rules of verb conjugation, where present perfect constructions require the past participle rather than the simple past form of the verb.