Unbound type constructor

[snowfall]

Hi.

I am developing a compiler for a language. I have done the parser, the lexer and the ast. But when I execute the command ocamlc -c parser.mli is shown the error "unbound type constructor abacus_ast.progr".

Here is the code of the AST:

open Lexing

type ident = string
;;

...

type progr= ident * (tipo list) * (declaracao_de_variaveis list) * (funcoes list) * (instrucao list)
;;

and in the parser I put:
% type < Abacus_ast.progr > programa

Can anyone tell me what I am doing wrong?

Best regards