I think I found the problem.
function kmlDoObStart()
{
ob_start('kml_flashembed');
}
...
// Apply all over except the admin section
if (strpos($_SERVER['REQUEST_URI'], 'wp-admin') === false ) {
add_action('template_redirect','kmlDoObStart');
}
Basically, WP Minify also uses ob_start to search and replace things on the page. This also clashes with other plugins that use ob_start like Anarchy Media Player and All-in-One SEO. I've been meaning to fix this, but I haven't had the time to do research on how to fix it yet. I suggest you just turn off WP Minify until I release a new version that will probably fix this issue. I'm shooting for either this weekend or next weekend.