[eclipse-clp-users] error

while compiling the below program I get an error like this
 instantiation fault in +(_593, 1, _597)
what is this mean and what should I do to remove this.Help me asap..
here is my program
:-lib(ic).
:-lib(branch_and_bound).
 solve(N,X):-
 dim(X, [N]),
 X[1..N] :: 1..49,
 %Z :: 1..49,
 (
   for(I,1,N),param(X,N) do
   (
     for(J,I,N),param(X,I) do
    (
       for(K,J+1,N),param(X,J) do

       X[K]-X[I]-X[J]#\=0
     )
    )
  ),

X =.. [_|Vars],
labeling(Vars).
one more I query i have tha If a optimization problem has more than one
solution how could I get all of its solution. Till now for getting multiple
 solution of  a COP I am doing that by converting the problem it into a
CSP.please tell me the other way to doing this.Expalin with example.
So please tell me if there is  an nother method