GETTING A BEAT INTO SONAR

I'm tryin to figure out why i cant get my beats to record into the computer. I have a triton,a mpc2000xl,a pentium3 computer w/ a regular soundcard and behringer 1002 mixer.I dont know why all the sudden my beats wont record into the computer now, before they did. and i think it has something to do with this cheap ass mixer i got. i already chose line in option on the computer, turned up the volume, put the microphone option on mute, all of that stuff but my beat still wont play. if anyone has this mixer or knows about the options please explain it to me because i have the main outs going from the mixer to the the line in of the computer but i dont know if i have the wrong button pressed down like a fx button or what or do i have to have the main outs slider all the way up and have the volume on the channel down i have the audio out from the computer all the way up also ? i'm confused and frustrated because i have artists that are waiting for me to put these beats on cd so they can rap on them and i'm bullshittin so if anyone could help me it would appreciated.

In Sonar, what do you have your track input set to, is it the sound card you're using. Is the card activated in the OPTIONS:AUDIO screen? Are you enabling the correct track for recording? When you do, are your level meters moving? Are your cables in the correct order? Try taking the mixer out of the loop and connect the MPC to the soundcard and see what happens, if the above doesn't work.