The arstechnica RSS feed works OK for me! Are you sure you defined the user module correctly? Did you click the 'use rss module' when creating the user module? In the 'Data' field you should have seen something like:
where 'rss id' maps to the numeric id of the RSS feed you have defined before.
Finally you must assign the custom user module to a location on the screen and to a number of user groups.
RSS feeds do not use port 119, the news reader/server connections use this port