when your configuring in the manage-> systems page you have a option of testing the remote machine, did u try that? and also as error shows "WebApplication server" are you trying to access the correct url or exact port. since the default port is 80 for http and 8080 for jboss(if ur using)
You need to make sure the agent is installed on the remote PC and ensure it is started and listening on port 9001. You will only be able to communicate with agents on the same network - at the moment OLT does not support using an agent in a remote network.