During a new ConfigMgr installation, I get the following error: "Setup could not install SQL RMO, ConfigMgr installation cannot be completed". I did a lot of ConfigMgr installations before, and thought everything was set right. A forum post was mentioning you need to download Client setup files again, instead of using existing ones. That did however not the trick! Let's have a look at this strange error.
On Gerry Hampson Device Management the following solution is mentioned: 1. Go to your download prerequisites folder. Uninstall the SQL Management Object by executing SharedManagementObjects.msi. Run the ConfigMgr setup again. or 2. Go to your download prerequisites folder. Install sqlncli.msi and SQLSysClrTypes.msi manually. Run the ConfigMgr setup again.
In my case it wasn't possible to install or uninstall SharedManagementObjects.msi. Installing sqlncli.msi wasn't possible either because a reboot of the server was needed. So I did a reboot on the ConfigMgr server and installation went fine after all. Still strange the message mentioned in the wizard doesn't look like you need to restart the server before starting setup again! ;)
Hope it helps!