If this error happens consistently, then it looks like you added extra characters to the beginning of the file vault/core/model/encode/vw.php when you applied the fix in your other report (the error states that output starts on line 1, and line 1 doesn't send output). It's possible the editor you used added extra invisible characters such as Byte-Order Marks. If there is a distinction in the program, make sure your editor encoding is set to "UTF-8 without BOM" rather than "ASCII" or "UTF-8". You will have to remove the extra characters or replace the file you edited with the one from the ZIP.