Issue with cubase SX3

hi musicians out there… im using cubase SX3, using M-audio audiphile as my soundcard and a Behringer line mixer. I have a problem. in audio track 1 i used it for my music minus 1. when i tried to record my vocals in track 2 the music in track 1 automatically recorded in track 2 where im supposed to record my vocals. pls help me out thanks!

What do your input buses look like? Do you have them set up correctly? Screenshot may help.