you can't include a file into a variable like that, AFAIK. You probably could, if you would then use eval(), which won't work in the block either.
The OP either needs to rewrite the code in the input file to adapt it to the needs of the block environment OR he could try something like this:
PHP Code:
<?php
ob_start();
include($file);
$result = ob_get_contents();
ob_end_clean();
?>