Learning STP2 and running into a large issue

Hello,

I'm a student trying to learn as much as I can during the summer break, so I ordered myself a bunch of Apple Pro Training Series books because I thought the Final Cut Pro one worked pretty well.

I sat down and decided to make book #1 STP2. I'm only on lesson 2 and I've encountered a deafening problem. I'm trying to reduce noise, so I highlighted a portion of the track where there's nothing but noise (even the same bit they highlighted in the book) and set Noise Print, then opened the Reduce Noise box. When I click play from within the box the left channel will be normal, but the right channel will randomly choose a different decibel level each time I click play. It'll go down to -96, up to 6, back down to -96, then as high as the 500s. I'm afraid it's going to blow my speakers.

If anyone knows what is going on with this please let me know. It's
pretty discouraging to hit a standstill at the 2nd lesson in the book. This only happens when I press play in the Noise Reduction box.

My system is a Mac Pro 2x2.8ghz quadcore intel xeon, 2 GB RAM, ATI Radeon HD 2600, Leapord

Also, does anyone know of books that present "If this is happening, then you did this:" type scenarios? My only gripe with learning programs through books is that they don't contain much trouble shooting info.

Thank you