No, there 're no errors during installation about certificate. And i haved same think after start8 installation.
In the fact, the certificate can be installed, and it may be a problem when an user do it.
As I have said before, no certificate is installed.
In theory a user could right click on a signed file, go to digital certificates, view the certificate and click an install certificate option (from explorer itself), but even if they did this there is no security issue or harm what so ever. The certificate cannot be used to sign anything, it is purely something that the OS is using to check that a file is validly signed (which it is if signed before that expiry date)
Expiry dates on certificates like that are normal. Often certificate issuers only issue certs for 1, 2 or 3 year periods so no doubt you have many files on your computer signed with expired ones. As long as they were valid when they were signed (which is what the timestamp signing is for) there is no problem as the OS checks that. It will however reject anything that is signed after the expiry date OR has no date at all if the certificate itself has expired.
In short there is nothing to worry about at all here.