When using Skype as your default dialing program, and Internet Explorer as your web browser, if you receive a Page Cannot Be Displayed error after clicking the phone icon, this is due to a lack of plugin present. To install the Internet Explorer plugin for Skype, simply run the Skype setup again. On the first screen of the Skype setup, click the Options button at the bottom-left. In the new window, check the Install Skype plugin for Internet Explorer checkbox. Once this is checked, complete the rest of the setup. 

After the setup is complete, you may need to close Internet Explorer and open a new page, then try to dial again. The error should be cleared at this point.