PGAdmin III Server Status Error: Could not read directory "pg_log" No such file or directory
Your client (Windows) is running on a different machine than your server (Ubuntu).

You cannot read the remote file system. Inspecting the logs only works if your client is on the same machine (or has access to the remote file system by way of some advanced trickery.)

To suppress the error message remove the log file from the display.
In the Server Status window press 
Ctrl-Alt-F
Or uncheck View -&gt; Logfile.