PHP timeout 120 exceeded - Only with large attachments - Not php.ini issue!

[blove57]

I checked the forums on this error and they all lead to dead ends- plus the forums are starting to flood with this new problem. This has been a problem since 2006. The problem is that when I send an email with an attachment larger than about 5MB, the compose message gets stuck with the "Sending Email" spinning icon at the top. The thing is that the email does get sent! It just hangs trying to save the email to the sent folder I believe because if I kill the the compose message and go to my sent mail, it's not in there. But the message got sent and can be opened on the recipient end. This is not a php.ini problem! I think there's some kind of bug- I'm using Windows by the way. Is anyone else having this issue?

My logs say:
[17-Apr-2008 18:43:51] PHP Fatal error: Maximum execution time of 120 seconds exceeded in C:\roundcube\program\lib\imap.inc on line 2455

This is pointing to which apparently is a Windows thing isn't it?:
$sent = fwrite($fp, $message."\r\n");