The error means that your mysql_query() returned FALSE, i.e. MySQL was unable to process your query and returned an error code. It's probably due to not having a "FROM" in your query. In any case, you can debug by doing something like this:
$sql = "SELECT * $housesTable WHERE house_id='".$select."'";
$number = mysql_query($sql) or die("Query failed ($sql) - " . mysql_error());
$row = mysql_fetch_array($number);