Is Sophos the Secret Behind Gmail Slowdown?

Update to the Gmail slow mail workaround I reported on yesterday. It seems the holdup may be due to the virus scanner used by Gmail. When I logged into my Gmail account to retrieve a password-protected file from the Sent folder, there was a message above the attachment that read, "Oops... the virus scanner has a problem right now. Download at your own risk, or try again later." Turns out, too, according to this report, that Google Gmail is using the Sophos scanner.