PROGRAM ERROR 1040. Press any key

Visual Prolog 5.2, ошибка:

PROGRAM ERROR 1040. Press any key

PREDICATES
    nondeterm travel(symbol, symbol, symbol, symbol, symbol)

include "C:\\USERS\\USER\\DESKTOP\\MCHI\\LAB1\\COMPANY\\ROUTE.PRO"

CLAUSES
    travel(A, C, A, C, Transport) :-
        route(_, A, C, Transport).

    travel(A, C, A, B, Transport) :-
        route(_, A, B, Transport),
        route(_, B, C, _),
        A <> C,
        A <> B,
        B <> C.

    travel(A, C, A, B, Transport) :-
        route(_, A, B, Transport),
        travel(B, C, B, C, _),
        A <> C,
        A <> B,
        B <> C.

    travel(A, C, A, C, Transport) :-
        route(_, C, A, Transport).

    travel(A, C, A, B, Transport) :-
        route(_, C, B, Transport),
        travel(B, A, B, A, _),
        A <> C,
        A <> B,
        B <> C.

    travel(A, C, A, B, Transport) :-
        route(_, A, B, Transport),
        travel(B, C, B, C, _),
        A <> C,
        A <> B,
        B <> C.

    travel(A, C, A, B, Transport) :-
        route(_, B, A, Transport),
        travel(B, C, B, C, _),
        A <> C,
        A <> B,
        B <> C.

GOAL
    travel(A, C, A, B, Train),
    write(A), write(" to "), 
    write(C), write(" via "), 
    write(B), write(" the one is transport a train "), nl,
    fail.