Error "please specify a valid megawizard generated variation file" (newbie)

Hi all,

When i try to regenerate the FFT megacore files, I chose fft_small.v and get an error "please specify a valid megawizard generated variation file".

Step 3 of Quartus II Compilation in "FFT 32K Point Design Example v1.0.0 README File".

help me!... thanks all.

I use : Quartus v9.1 web edition