Hello Mike,
I have the same problem. The same message appears briefly any time I access my
website. 
I don't think I used the base path to upload the website.
Here is what I did (apologies if it sounds naive, I am not an expert):
I started a new project, gave the projest a name and left Project category
empty. For Base path I selected my desktop. I added the URL and completed
mirroring. Then I transferred the project folder (not the base path) to the
hosting site. Everything seems perfect besides that portal page that always
shows up for a few seconds.