Problem with foreign key between 3 tables. (PgAdminIII) I'm using pgAdmin III for PostgreSQL but I have a problem with foreign keys between 3 tables. My tables are:

Locale with a primary key IDnegozio (integer type, no need to make it serial type)
Orario with a primary key IDorario (integer type, no need to make it serial type)
OrarioToLocale with two columns: IDlocaleT &amp; IDorarioT (both integer).

I'm trying to make a foreign key between IDlocale -> IDlocaleT and IDorario -> IDorarioT so, I can have the relation that a Shop can have multiples time.
The problem is that when I try to make these foreign keys, and an error occurs me: 
"no unique constraint matching is given keys for referenced table" and I don't understand why. I tried to google but I didn't find any answer!
How can I do?

This is the code of the three tables:

CREATE TABLE public."Locale"
(
  "IDnegozio" integer NOT NULL DEFAULT nextval('"Locale_IDnegozio_seq"'::regclass),
  CONSTRAINT "Locale_pkey" PRIMARY KEY ("IDnegozio"),
)

CREATE TABLE public."Orario"
(
  "IDorario" integer NOT NULL DEFAULT nextval('"Orario_IDorario_seq"'::regclass),
  CONSTRAINT "Orario_pkey" PRIMARY KEY ("IDorario")
)

CREATE TABLE public."OrarioToLocale"
(
  "IDlocaleT" integer NOT NULL,
  "IDorarioT" integer NOT NULL
)


How can I do? Thank you advice!
It would have been good if you provided the foreign keys that failed. The following should work:

ALTER TABLE public."OrarioToLocale"
    ADD CONSTRAINT FK_... FOREIGN KEY ("IDorarioT")
        REFERENCES public."Orario" ("IDorario");


and a similar constraint for Locale. Why do the attributes in OrarioToLocale end with a T?