Error C2352: illegal call of non-static member function

I have defined below class

    class CFourier
{
public:
    double pi;
    unsigned long int fundamental_frequency;
    float *vector;
    CFourier(void);
    ~CFourier(void);
    void ComplexFFT(float data[], unsigned long number_of_samples, unsigned int sample_rate, int sign);
};

and defined below:

CFourier::CFourier(void)
{
    pi=4*atan((double)1);CFourier::vector=NULL;
}

CFourier::~CFourier(void)
{if(CFourier::vector!=NULL)
        delete [] CFourier::vector;
}

// FFT 1D
void CFourier::ComplexFFT(float data[], unsigned long number_of_samples, unsigned int sample_rate, int sign)
{

    //variables for the fft
    unsigned long n,mmax,m,j,istep,i;
    double wtemp,wr,wpr,wpi,wi,theta,tempr,tempi;

    //the complex array is real+complex so the array 
    //as a size n = 2* number of complex samples
    //real part is the data[index] and 
    //the complex part is the data[index+1]

    //new complex array of size n=2*sample_rate
    if(vector!=NULL)
        delete [] vector;

    vector=new float [2*sample_rate];

    //put the real array in a complex array
    //the complex part is filled with 0's
    //the remaining vector with no data is filled with 0's
    for(n=0; n<sample_rate;n++)
    {
        if(n<number_of_samples)
            vector[2*n]=data[n];
        else
            vector[2*n]=0;
        vector[2*n+1]=0;
    }

    //binary inversion (note that the indexes 
    //start from 0 witch means that the
    //real part of the complex is on the even-indexes 
    //and the complex part is on the odd-indexes)
    n=sample_rate << 1;
    j=0;
    for (i=0;i<n/2;i+=2) {
        if (j > i) {
            SWAP(vector[j],vector[i]);
            SWAP(vector[j+1],vector[i+1]);
            if((j/2)<(n/4)){
                SWAP(vector[(n-(i+2))],vector[(n-(j+2))]);
                SWAP(vector[(n-(i+2))+1],vector[(n-(j+2))+1]);
            }
        }
        m=n >> 1;
        while (m >= 2 && j >= m) {
            j -= m;
            m >>= 1;
        }
        j += m;
    }
    //end of the bit-reversed order algorithm

    //Danielson-Lanzcos routine
    mmax=2;
    while (n > mmax) {
        istep=mmax << 1;
        theta=sign*(2*pi/mmax);
        wtemp=sin(0.5*theta);
        wpr = -2.0*wtemp*wtemp;
        wpi=sin(theta);
        wr=1.0;
        wi=0.0;
        for (m=1;m<mmax;m+=2) {
            for (i=m;i<=n;i+=istep) {
                j=i+mmax;
                tempr=wr*vector[j-1]-wi*vector[j];
                tempi=wr*vector[j]+wi*vector[j-1];
                vector[j-1]=vector[i-1]-tempr;
                vector[j]=vector[i]-tempi;
                vector[i-1] += tempr;
                vector[i] += tempi;
            }
            wr=(wtemp=wr)*wpr-wi*wpi+wr;
            wi=wi*wpr+wtemp*wpi+wi;
        }
        mmax=istep;
    }
    //end of the algorithm

    //determine the fundamental frequency
    //look for the maximum absolute value in the complex array
    fundamental_frequency=0;
    for(i=2; i<=sample_rate; i+=2)
    {
        if((pow(vector[i],2)+pow(vector[i+1],2))>(pow(vector[fundamental_frequency],2)+pow(vector[fundamental_frequency+1],2))){
            fundamental_frequency=i;
        }
    }

    //since the array of complex has the format [real][complex]=>[absolute value]
    //the maximum absolute value must be ajusted to half
    fundamental_frequency=(long)floor((float)fundamental_frequency/2);

}

but when I try to use the function ComplexFFT with

CFourier::ComplexFFT(sampleData,661500,44100,0);

I am getting error:

Error C2352: 'CFourier::ComplexFFT' : illegal call of non-static member function

Changing ComplexFFT into a static in the class doesn't help. All advise is very welcome as I am struggling with this for days now