I run a ST 530 on an Ethernet connection to my PC.
Have you got the installation disk that goes with the 530 ? You should be
able to set up following the menu on the installation disk.
Another thing to check is the firmware. The current is 4.2.5.0.0 which
includes an "Easy Setup" wizard to help set up too.
Check the Speedtouch UK website
http://www.speedtouch.co.uk/index.asp for
their downloads of current drivers and setup advice.
There is a downloadable 530 users guide on this page
http://www.speedtouchdsl.com/support.htm