Garageband situation

Last Thursday I had a few friends over to record our first practice. I wanted some material to sharpen my skills recording wise as well as getting songs for a new music project. We recorded three songs, very rough but serviceable for the task at hand.

We had 2 electric guitars, bass and three vocals going though a Sapphire Pro 40 interface going into Garageband. Microphones used were 2 SM58s and an EV N/D767a. This is the first time I recorded with other people at the same time with this gear. Any other time it was just me doing everything.

I noticed I had to really crank the mic pres on the Saffire to around 3 o'clock. I later backed off once we ran down a song a few times to get the grit out.
We then recorded a version of The Last Time and at the same point in the song the "feedback detector" would trip in Garageband. We were going through headphones only, the mains were turned off but every time we hit that same part, the detector would trip again. I pulled all the levels back and we managed to get through the song.

Does anyone know how to defeat this function?

Don't know what version you're using, but with GB '09:

ctrl-click the record enable button on the audio track(s) and select Monitor Off or Monitor On (no feedback protection).

Don't know what version you're using, but with GB '09:

ctrl-click the record enable button on the audio track(s) and select Monitor Off or Monitor On (no feedback protection).

It's the latest version.

Did what I suggested work with the new version?

If not, can you go to view track info (or where ever you select the Input Source: Mono 1 Saffire, for example). Is there an option beneath that to change monitor settings to Off, On, or On (no feedback protection)?