Corrections:

I am not aware of any other errors in the book. If you suspect you've encountered an error, please submit it through the Contact Form.
Extras:
Help with formulas. Go to the Cut&Paste Formulas page where I have assembled many of the longer, more complicated formulas from the book.
Don't have Excel? Click the following link to see my Notes on using the Free Calc Spreadsheet Program. As another option, you can try using the online spreadsheet program in Google Docs. I only did minimal testing in Google Docs, but it looks like you should be able to do most of the examples there.
I've put together an article on Excel's Forecast Function and posted it on my main site. It has some additional examples you may find helpful. There's also an article on Component Safety Stock that has some additional information not in the book.