If the OS is SnowLeopard, then check if there is a crash of Installer process while installing the product via ePO.
You can also check McScript.log under /Library/McAfee/cma/scratch/etc/ to see what happened at the moment when install was being initiated.
If you see a crash for installer process, then just restart the McAfee Agent service via sudo SystemStarter restart cma and then try the deployment.
ssh is only required to install McAfee Agent via ePO. Product install doesnt need ssh as McAfee Agent would handle the deployment with its own creds which is root.
When you state that you are having issues with the deployment, can you explain a bit more of what you are doing? I ask, because we have a similar issue that Mac systems are unable to communicate with the EPO server if their hostname matches that of another machine. With Windows computers, the hostname is provided to DNS. However, with Mac systems, they seem to pull the last hostname associated to the IP from the DNS server. EPO server uses the IP address to communicate with systems, but if the hostname assoicated with the IP is different than that of the Mac, you may see some issues when deploying the agent.
Is this similar to what you are experiencing? Can you expand a bit?
We've run into 2 issues that for use have been the main cause of deployment failure. Firstly the power saving settings by default cause the systems to sleep too quickly and will continuously fail deployment if the users are not at the machine long enough. Secondly we had a lot of users using the wireless instead of wired network and our University purposely performs random termination of large file transfers on the guest wireless to prevent the use for downloading illegal software. This would cause the deployment package to keep being cut over and over again.