Thank you: http://casualtechs.blogspot.de/2010/06/problem-when-trying-to-import.html
Download and save the certificate.
Open the Certificate Manager
In the “Start Search” box, type “certmgr.msc” (no quotes).
The certificate manager will open.
Right click on “Trusted Publishers” from the folder list on the left.
In the pop-up menu, choose “All Tasks” >> “Import..”
Click the “Next” button
Click the “Browse” button
Browse to the location where the certificate is saved, click on it then click the “Open” button
Click the “Next” button
Select “Place all certificates in the following store”
Click the “Browse” button
Put a checkmark beside “Show physical stores”
Expand the “Trusted Publishers” folder
Click “Local Computer”
Click the “OK” button.
Click the “Next” button
Click the “Finish” button