Long story short, I'm not sure if you've received my email. Please let me know.
If anyone else runs into this issue, please edit main.inc.php line 68 from
require_once $_SERVER['DOCUMENT_ROOT'] . ROOT_PATH . "/osta/php/functions.php";
to
require_once "osta/php/functions.php";
After doing that please try uploading a new company logo. If that works for you I reckon that email piping will, too. Please let me know asap so that I can include this fix in the next release.
I haven't heard back from you. I've gone ahead and included this fix in the latest release, which is available now on the Downloads page. I am confident that it will resolve this issue.
I will mark this as resolved for now, but please don't hesitate to post an update at any time.