After some tests, I've found a cause of the problem.
It seems that Seam or Hibernate refuses the table names with more than one underscore character.
In a new test project, the app works fine with the same definition of the table t_e_personne_prs but with the simpliest name personne_prs.
The name t_personne_prs causes the error.
Somebody knows what are the restrictions about the names of the tables ?
Or is it a bug ?