Is there an error message in the log window?

Is it possible, that you have an other web server listening on port 8080? You can check this, by opening http://localhost:8080/ in your browser.

Log Window now says:

Checking for new version...
Downloading webapp properties: http://kunagi.org/katokorbo.properties
Downloading version properties from <http://kunagi.org/katokorbo.properties> failed: Connection timed out: connect
ERROR: Downloading from <http://kunagi.org/katokorbo.properties> failed.

I do not know how installation works in Windows, I have extracted Windows exe and this shows up in log window.
Can you please give me detail procedure about Windows installation?

Also opening this URL http://localhost:8080/ shows me `Unable to connect` on browser.

The kunagi.exe on windows is a tool which downloads the latest kunagi and runs in in an embedded Tomcat. This is a good solution for testing and for small installations. The error message ''ERROR: Downloading from <http://kunagi.org/katokorbo.properties> failed." means, that the tool was not able to acces the URL. Perhaps you have a firewall blocking the connection?

If you are an admin, I would recommend to download and install Apache Tomcat and then put the kunagi.war into its webapps directory. That way Kunagi does not require a connection to the internet.

'ERROR: Downloading from <http://kunagi.org/katokorbo.properties> failed." means, that the tool was not able to acces the URL. Perhaps you have a firewall blocking the connection?

--> I can access other URLs than this, also i have tried changing proxy settings as well.
Anyway I will try to install the other way you have mentioned.