You appear to be attempting to use SAS Macro syntax in a JMP script. &i is not valid for JSL.
One way to handle what you are attempting to do in JSL is
Names Default To Here( 1 );
dd = Current Data Table();
i = 1;
Eval(
Substitute(
Expr(
__xxx__ = dd << Subset( Output Table Name( "i" ), All Columns( 1 ), All Rows( 1 ) );
//Graph table
__xxx__ << Select columns( :As is Config );
),
Expr( __xxx__ ), Parse( "newdt" || Char( i ) )
)
);
Documentation on this is in the Scripting Guide. You need to take the time to read through the documentation.
Help=>JMP Documentation Library=>Scripting Guide
Jim