[wp-hackers] Theme functions.php Encoding Weirdness

[Jeremy Visser]

On Sat, 2008-01-12 at 19:24 -0800, Matt wrote:
> In Trunk, if the theme's functions.php has the encoding UTF-8, I get the
> following error when editting settings:
> 
> *Warning*: Cannot modify header information - headers already sent by
> (output started at /path/to/wp-content/themes/themename/functions.php:1) in
> */path/to/wp-includes/pluggable.php* on line *600*
> 
> But, when I changed functions.php to ANSI, there was no error.
> 
> The settings are still changed, though.

Possibly there is a BOM (byte-order mark) sneaking in there somewhere.
Try looking at it in a hex editor.