The first step is "Logging On" to Reuters DataLink, which is attempting to authenticate your account over the appropriate data port (7983 for North American data).
If this port is being blocked, you will never get past "Logging on to Reuters DataLink".
The next step is to open an FTP connection. This uses FTP port 21. If you are getting stuck at "Waiting for Data" it is very possible that FTP is being blocked.
You would need to make sure the following addresses/ports are opened:
quotes.reutersdatalink.com (192.165.218.19) on port(s) 7983 through 7989
192.165.218.23 on port 21
192.165.218.24 on port 21