I Need your help

I have a tech prob my record output left/right only plays on the left on two
separate line ins on my Mackie 1202 meaning both left and right plays but
only in the left inputs on the mackie.

Also prob. no.2 is my record level when sampling is not high enough
when I turn up the rec gain their is humming and too much action
the record level doesnt go high enough to initiate the sample and Im
new to the Mpc so if someone can be kind enough to show me the
ropes I would greatly appreciate it

P.S. I have a Mbox setup

Your post is still not clear to me, do you sample from a turntable? is it grounded? If you have hum there can be a ground loop maybe, explain your whole setup and let's attack these questions one at a time. As for your first question, what cables from/to the mpc are going to what inputs/outputs where on the mackie?