Since the "Moderator" has locked the previous thread where this was being discussed, I will post here, because there is more information to be shared.
I just received this response from CyberLink (typos and all):
The error you are recieving while accessing the YouTube.com is due to the firewall settings of your computer or network which is preventing the browsing of YouTube.com.
Please ensure that you can access the YouTube.com site from you browser.
If you can access the web-site through a browser and not through the YouTube.com then please let us know.
I am not having problems connecting to YouTube.com, and I suspect neither are any of the many other folks who have reported this problem. So either R&D is not talking to Customer Support (which is a good possibility), or they still do not understand the problem. Either way, it does not bode well for a fix anytime soon....