Not my strong point but will try to help as I can.
If you can get 1 channel then likely a setting is messed up, scanning argentina layout while in USA has different transponders and by luck is picking up a channel.
Cable signal strength has to bee good or plugged into external rooftop antenna instead of the small antenna that comes with the card as likely the scanning software has too low sensitivity setting to pick up the weaker channels.
Mine did this in windows in UK.
Now only have dvb-s feeds and dvb-t cards here = no joy aarrgghh.
PS: the card is dvb-s or dvb-t or dvb-c or combo and your target signal is what format dvb-??? , might ahve to check this setting in the scan software's config and adjust to get best results.
Have a look at some of the google search links:http://www.google.com/search?q=saa7134+ ... =firefox-a
IVTV:http://www.google.com/search?hl=en&safe ... tnG=Search