I followed the manual instructions for making a Lineweaver-Burk plot, but the line isn't right. Why?

There was an error in the steps presented in the Help for Prism 5. The second and third steps should be:

2. Into row 1, enter X = -1/Km (previously determined by nonlinear regression), Y = 0.

3. Into row 2, enter X = 1/Smin (where Smin is the smallest value of [substrate] you want to include on the graph) and Y = (1/Vmax)(1+Km/Smin).