use FFT in matlab and get phase plot

i have some polymers characterized by transmission terahertz time domain spectroscopy (THz-TDS).

ive now the time domain data in Excel, with column A being (Delay ps), column B (Reference), column C (Amplitube nA) as follows.

**broken link removed**

i would like to have "FFT phase of column C" minus "FFT phase of column B", and then plot the phase (after deduction) as a function of frequency.

i am told this could be done by adding

plot(freq,angle(fft(X,3)))-angle(fft(X,2))))

after

[X,TXT,RAW] = xlsread('yourfile.xls');
xdft = fft(X,2)); xdft = fft(X,2));
% sampling interval -- assuming equal sampling
DT = X(2,1)-X(1,1);
% sampling frequency
Fs = 1/DT;
DF = Fs/size(X,1);
freq = 0F:Fs/2;
xdft = xdft(1:length(xdft)/2+1);
phi = angle(xdft);

anyway it does not work

the command window shows

??? Error using ==> plot Vectors must be the same lengths.

Error in ==> Untitled at 12 plot(freq,angle(fft(X,3)))-angle(fft(X,2))))