Waveform not showing anymore...

Hello there.
Well, I've been using my recently bought MBP and bumped into this incredible program named GarageBand.

What happens is that I play electric guitar, and I have a P10/P2 cable, meaning I can plug it directly into my MBP.

The first songs I played and recorded went ok. But the problem is that now, the waveform lines on the loops are not showing anymore.

I mean these (grabbed this on the web, not my own GB):
http://z.about.com/d/homerecording/1/0/m/1/-/-/garage6.jpg

I don't know exactly how you call this in English, maybe "samples", or "tracks", but the fact is: as I record the sound from my guitar, the line is not moving anymore; it stays as a straight line, as if I wasn't playing anythin at all. It was moving in the first songs, when I touched the strings the line would come up, but now it doesn't move. Funny thing is that I can PERFECTLY hear the recorded sound. I set the volume to maximum, and every single bar of volume is hitting the red sections...

Ok so a quick look: the waves on the recording lines are not showing anymore, but the volume is loud. I can record and play the tracks without any issues (and export them to MP3 too).

I tried changing the Input to Mono 1, Mono 2, Stereo, but I always get the same. Did I do something wrong? Is my cable not working well? it's a new cable ):

So the question itself: *What can I do to the Waveform lines show correctly (again)?*

thanks in advance.

Message was edited by: Cleberson

Message was edited by: Cleberson