Well it's not 'Wrong' persay, but you don't need all the () on your multiplication operations.
It could just be
=IF(E5=1,H5*I5*G5,H5*I5)
Other than that (and the missing = at the beginning), there is nothing 'wrong' with the formula
Why don't you tell us what the symptoms are...
In what way is it not working for you?
Do you get an error? What error?
Do you get the wrong result? What result DO you get? And how is that different from what you expected?
What are the values of all the cells involved?