Error: operator does not exist: integer = integer

[Clodoaldo Neto <clodoaldo.pinto.neto@xxxxxxxxx>]

postgresql.x86_64                             8.3.14-1PGDG.rhel5
postgresql-server.x86_64                      8.3.14-1PGDG.rhel5

ERROR:  operator does not exist: integer = integer
LINE 3:            inner join vendedor as v on a.vendedor_id = v.id
                                                             ^
HINT:  No operator matches the given name and argument type(s). You might need to add explicit type casts.

Any ideas?

Regards, Clodoaldo