If you're using the comb with weights, I'd recommend adding more weights. Ribbers take more weight than you'd think to work properly.
That said, machine knitting is a such a niche hobby. And there is only one manufacturer currently in business, Silver Reed. That makes getting info harder by the day, as Brother, Singer, KnitKing and the others no longer make machines. But mercifully there is a lot of info available on the net.
Check out some of the sites listed on this page:http://marciahauser.tripod.com/page4.html
. Northtipton is good, and I highly recommend Ilene Levy's site too.
One that isn't listed on that page is Country Knitting of Maine's Yahoo Group. I highly recommend them as a resource. Linda is highly knowledgeable as are her list members. And they're quite friendly too! Here's the link to her Yahoo group. http://groups.yahoo.com/group/countryknittingofmaine/
. Join up , and ask questions as needed. There are other Yahoo Groups dedicated to machine knitting too.
As GG said, this forum is primarily hand knitters - about the only thing hand and machine knitting have in common is yarn - but one of the Yahoo Machine Knitting Groups can help you out.