Roger,
So your Integration server is installed in some other host (say X) and you have Tomcat installed in your local machine (Y). You are trying to call Tomcat URL from Integration server. Provide your machine host name when you send request from Integration server. If IS detects something as localhost, it will try to check in the same machine (X) if the specific port is listening or not. Modifying your etc/host file will not help.
-Senthil
#soa#API-Management#webMethods