Someone please help me start mining on Windows 7   .. I've been trying for hours and I still can't connect using 127.0.0.1 -- it just keeps saying json_rpc_call failed

This is what I have so far cudaminer.exe --algo=keccak -d 0 -o http://127.0.0.1:8108 -O username:password -i 0 -C 2 -l F14x16 -m 1

I have GTX480.   What should I use for command line?  And what should I replace username and password with?