It's ok - I just need to reign you in until we make sure everything is working.
I know you got excited, but we just need to finish this as methodically as we started, because THAT's what worked to get us past all of that other junk.
So, at this point, you are in your project, you have ASIO specified for your drivers, sampling rate is 44.1 in Sonar and in the interface itself, you have an audio track with an imported MP3, and when you hit play you get no output.
If the above is not correct, then please post back immediately with any corrections. I am going to start composing another post, based on the above understanding, while you read this one.
Bob Bone