This has been addressed befor but you have an esxapr character that must be escaped your code
$junk = array('.' , ',' , '/' , '\' , '`',';' , '[' , ']' , '-',
'*', '&', '^', '%', '$', '#', '@', '!', '~', '+', '(', ')',
'|', '{', '}', '<', '>', '?', ':', '"', '=');
should be
$junk = array('.' , ',' , '/' , '\\' , '`',';' , '[' , ']' , '-',
'*', '&', '^', '%', '$', '#', '@', '!', '~', '+', '(', ')',
'|', '{', '}', '<', '>', '?', ':', '"', '=');
See the difference after the value for '\'? This is in a tutorial that needs to be corrected.