Hmm,my thoughts:
1-Feedback is caused by bad routing. The simple solution, for a simple live recording is to mute all the tracks(they still record just fine).
2-One of your uploaded sound files is name "high drive guitar amp...", is that a plugin amp sim or a mic on a real amp?
3-Most of the noise in all the examples doesn't sound like feedback to me. It sounds like serious interference. If you are using a laptop, try running it on the battery to see if anything changes. If not, try moving the computer and interface as far as cables allow. Or try getting your AC power from somewhere else.
4-If none of this helps, describe the entire setup in great detail(its impossible to give too MUCH information)
