cant install anything

i am running opensuse 11.1 but the kde3.5 version i imstalled it about 6 weeks ago and everything was fine i could download a rpm or ymp file aqnd yat would install the program with no issue. but then i changed my video card and linux just would not work after that. so i reinstalled and everthing is working fine but now when i try to install a program yast tells me “files not found at specified url’s” and “check if server is available” it’s been a few weeks now and i was wondering if im doing something wrong or is a server actually down?