Accessing FFTW from ROOT

I was trying to use TVirtualFFT from ROOT 5.14.00b on
afs at cern (linux) and this requires installing and
accessing FFTW in ROOT. Although I seem to have compiled
FFTW, I was unable to load to ROOT as a sharable lib.
When I did gSystem->Load("…/libfftw3.a");
I got “dlopen error: …invalid ELF header”.
I was wondering if there is an FFTW library that is
in the ROOT area that I can directly load or if
there is any options I can use when installing FFTW for this.