Oracle forms where clause with a variable from bloc item

I'm trying to populate a block using a FROM clause in oracle forms like this:

select h.no_ordre, h.marge,h.date_modification, h.utilisateur_modification from hist_marge_0alb h, simul s, simtauxvar_0alb sv, affaire a where s.id_affaire = a.id_affaire and s.id_simul_element(+) = h.id_simul_element and sv.id_simul_element = s.id_simul_element and s.id_affaire = :SIMUL.id_affaire

But i got a FRM 40505 Error. I think the problem is in :SIMUL.id_affaire but I don't find a way to do it. Is there a way I can do it? Thanks.