Forget the helpers

create a form upload element on your form

<form enctype="multipart/form-data">
    <input type="file" name="myfile" id="myfile" />
</form>

in your controller do this:

if( $this->Request->isPost() ) { //see if a form has posted.
    //echo '<pre>' . print_r($_FILES, 1) . '</pre>'; exit(); //uncomment this line to have a look at the $_FILES array
    if( file_exists( $_FILES['myfile']['tmp_name'] ) ) {  //check to make sure the file exists.
        move_uploaded_file( $_FILES['myfile']['tmp_name'], $uploads_dir.'/'.$_FILES['myfile']['name'] );  //do something with the file
    }
}

Just an added note. On unix systems checked your php.ini to see where the tmp directory is. Most systems specify /tmp . Make sure it is writable by everyone (i.e. chmod 777 /tmp )

-- Pogeybait