The client could not establish a connection to the remote computer.
The most likely causes for this error are:
1) Remote connections might not be enabled at the remote computer.
2) The maximum number of connections was exceeded at the remote computer.
3) A network error occurred while establishing the connection.
Yesterday I was troubleshooting for a user why she was not able to do a remote desktop to a server through Sonic Wall Remote Office. I encounter the above error when establishing the rdp connection, I cannot find any errors in the event viewer of the client computer. She was using firefox, but the moment i use Internet Explorer to initiate the rdp, i saw the an error message popup. Quickly apply the below patch for the user.
For Microsoft Windows XP Professional with Service Pack 2 and Terminal Services Client 5.0. You need to download this ms patch KB884020 when doing rdp to lookback address e.g. 127.0.0.2