Hi Vinod Kumar Akurathi,
This is a very generic error and could be caused by a number of issues. The first thing I would suggest is to see if you can access the Web Services through the URL (Should be able to locate it within the Web Intelligence Rich Client). If you can access the Web Service through your browser, I don't suspect it's an issue with your Tomcat server.
If you can't access it, stop the Tomcat server, clear out the cache directory ($CATALINA_HOME\work\Catalina\localhost), and start the Tomcat server. Try to access it again. If you're still unable to, check to see if it's a network issue, as it could be that you're unable to connect to the various servers.
The next place to look is to see if multiple people are receiving the same error. It could be a network issue from the individuals desktop to the server, or it could be report related. This way, you can narrow down the issue as if it's everyone, then more than likely it might be a connection issue between the desktop & server. If it's just one or two people, chances are it's a desktop related issue.
If all else fails, see if you can use Fiddler or WireShark or some form of HTTP trace to see where the connection is being dropped. This will help you identify the issue a bit more.
Let me know if this works or not or if there is a new error. Thanks,
-Victor