HELP! Prefix operator precedence error message

From: FirewallVictim (catazy_at_hotmail.com)
Date: 04/27/04 

Date: 27 Apr 2004 09:50:50 -0700

Could someone please help/advise with a small prolog problem i'm
having. Im fairly new to prolog and im only a beginner programmer. I
developed a small prolog program based on eliza in SWI-prolog for
windows but when i try and migrate it to UNIX im getting an error
message. Any advice would be much appreciated.

Code runs in windows but not in unix.

append([],L2,L2).
append([H|L1],L2,[H|L3]):-
        append(L1,L2,L3).
        
% Redefine append as ...
:- op(900,fy,'...').
...(X,Y,Z) :- append(X,Z,Y).

response(Response List) -->
                ..._, [keyword], ..._.
                
                
Error Message: Prefix operator precedence too high (HERE being where
error occurs)

response(Response List) --> <<HERE>>
                ..._, [keyword], ..._.

I get the feeling unix or prolog doesnt like the use of ... or the way
the rule is defined. Any pointers?

Thanks in advance