You seem to be making this way too complicated. Enter the IP address in the 'IP/Host' field - 192.168.1.138, click on the 'Load Shares' button and select the share you want. UD will take care of the rest.
If that produces errors or the NFS share doesn't mount, show a screen shot of what you are entering into the dialog for IP address and share, and the UD log so I can help troubleshoot. If you are entering all kinds of syntax trying to get the NFS share to mount, it is difficult to understand and hard to see what UD might be doing wrong.