When compiling your sample FFT I get:
BUILD LOG
************************************************
"/tmp/OCL6501T5.cl", line 115: error: no instance of overloaded function
"FFT::Init" matches the specified type
void FFT::Init(__global float *real,__global float *imag,__local float *Localds)
^
"/tmp/OCL6501T5.cl", line 678: error: no instance of overloaded function
"FFT::Init" matches the argument list
argument types are: (__global float *, __global float *, __local
float [2176])
object type is: FFT
fftObj.Init(greal,gimag,lds);
^
2 errors detected in the compilation of "/tmp/OCL6501T5.cl".
Frontend phase failed compilation.
Plz use attached sources. It should be, but is not exactly your sample.