Using Amplitube live

How can I hear the sounds from this (or any other) plug-in as I'm playing without the terrible distortion. This happens when I click the input echo - isn't this a monitoring device. I know it's a feedback/loop problem, can anyone tell me how I can get around it? Strange thing though, as I was trying to overcome this problem earlier, the distortion stopped and it worked great for about a minute, then started again and I'm not sure what I did (if anything) in between. The help doesn't help. Hope some kind soul out there can.
 
i3 quad core 3.2ghz, 6Gb ram, 64 bit windows 7, Sonar x1, Roland Quad Capture USB sound card.