INNER JOIN returning error

I'm trying an INNER JOIN between 3 tables plus error returns, I do not know what's wrong. Query:

SELECT
    aa.arq_arqid,
    aa.arq_nome,
    aa.arq_nomecrip,
    aa.arq_datetime,
    u_usuarios_u_userid
    a_area_a_areaid
FROM arq_arquivos as aa
INNER JOIN u_usuarios as usr
ON u_usuarios_u_userid = usr.u_userid
INNER JOIN a_area as ar
ON a_area_a_areaid = ar.a_areaid