By default when you install the Arcserve RHA engine service it installs on port 25000. If you are having communication issues with a particular server and you know the port you installed it on is open the issue may be that the engine is not listening on the requested port. It is always important to test that the port is open by doing a telnet to the server in question from the RHA management server and from the other servers in the scenario using the port you installed it on. If telnet works in all those directions the next thing to check is if the RHA engine is listening on the port you installed it on.
To determine if RHA is listening on the port you installed it on bring up a command prompt on the server in question.
* Type netstat -an (You can also type netstat -ab if you want the process name that uses each port listed)
* Scroll to the top and on the left column look for 25000 (or whatever port you chose to install the engine on)
* Once you find 25000 or your custom port, look to the right and in the right hand column you should see 'listening'. If you do not find your port in the list with the word 'listening' in the right hand column the RHA engine service is not listening on the requested port. You may want to go to 'edit' and then 'mark' and select all the data in the command prompt and then copy it and paste it into a text editer like notepad and then do a search for your port number.
If you do not find your port number anywhere in the list you should make sure the RHA engine service is running in windows services. If it is running and it is using a named account (domain or local admin) I would change the account to local system and then restart the engine and try the netstat command again in a few minutes.