I needed to re-install the C310 into P3D 1.4. The information on the website seems to be out of date:

http://milviz.com/fs/item.php?id=C310R

Download Information

To purchase, download the EXE below. Once you run the EXE, the purchase screen will appear. 

Notice: This is the latest version (1.012011) of the product. 

Download the MilViz C310R for FSX Here! (99MB) 

 

 

After downloading the .exe and running it, it turns out it actually contains v3.140420, so it's only the information on the website that is out of date. Caused a bit of confusion, though.

I just noticed this today.

 

F1 still has the old version as a download.

I think they went over to a different system where even the people who originally bought from F1 now get the plane direct from Milviz, not from F1, so whatever version F1 has no longer matters.

Send 'proof of purchase' info to colin at miviz.com and request the latest update link.

In addition to Fr. Bill's excellent (and 100% correct) advice, also note that the original link that the original poster listed is no longer valid; it redirects to the main Milviz page. 

 

This is as intended: the website has changed significantly. I just thought I'd post this bit of info for anyone who might be confused by the course of this thread.

I sent an e-mail and received a link to download the latest build. This took just a few hours. Excellent!