There is software that is blocking SwiftKit's access to the Internet. While it is hard to exactly fix the problem remotely because of different firewall/anti-virus programs, we can always help a little bit.

To test to see whether this is the case, please read this article.

Open your anti-virus or firewall program. Look for a place where you can set excempts or can allow/block certain programs. Make sure 'SwiftKit' or 'Toolkit for Runescape' is allowed or has special setting to allow it to connect to the Internet.