OK, what am I doing wrong here? I've sidechained in Sonar before but now it's just not working. I have a kick drum track and I want it to trigger the ProChannel PC4K compressor on the guitar buss. Created a send to the compressor from the kick drum, should be good, right? No dice. I turned the threshold and attack all the way down, messed with the release, made sure the compressor and send were on, nothing. Kick won't even register on the compressor. Help please!

Dumb question...but are you certain the side-chain function of the PC4K is turned on? The little switch to the "I" position? Also, is the Kick drum volume loud enough? Are you sending pre or post fader?

Try switching in the sonitus compressor which had the graphic that can help to set threshold etc. Then switch back. That might help with the trouble shooting.