How long are your beer lines now?
Not 100% sure of exact length, on this setup I have one of these http://www.craftbrewer.com.au/shop/details.asp?PID=3615 with the standard line it comes with. It's about 1m long, but supposed to have a 4 or 5mm internal size, so "should" be the correct length for it's diameter. I've been trying to avoid adding more length to the lines as the fridge is already pretty tight to get all the crap in there. My other older setup out back has long lines, as per the calcs you get for line length, and I've never had an issue.
QldKev