Here is how to fix GMail's false positive error. When you see this:
Virus warning - 1 attachment contains a virus. Downloading this attachment is disabled. Learn more

static.3ice.hu/images/GMail-virus-attachment-disabled-1--screenshot.png
And the download button is disabled:

static.3ice.hu/images/GMail-virus-attachment-disabled-2--disabled.png
Simply right click → Inspect element → scroll up a few lines and find the link to docs.google.com. It looks like this:

static.3ice.hu/images/GMail-virus-attachment-disabled-3--inspect-and-find-this-URL.png
Go there and now you can download:

static.3ice.hu/images/GMail-virus-attachment-disabled-4--now-you-can-download.png
p.s.: Yes, it was a false positive:

static.3ice.hu/images/GMail-virus-attachment-disabled-5--it-was-a-false-positive.png
GMail; protecting us so hard it suffocates us.
--3ICE