hola, Zac! Creo que no hay "acentos graves" en español. Sí los hay en el catalán por ejemplo, pero en el español creo recordar que no hay ninguna palabra que use ese tipo de acento. Saludoss

As Sergio says, in Spanish doesn't exist the grave accent (`), we only have the acute one (´). And about it, the answer is yes, definitely it's important. In fact, we consider a mispelling when a word which has to be written with it is written without it.