I am trying to use phenix and I was trying to do the following:

Take a PDB, generate a MTZ file using Calculate F (model) and lets call it 

native.mtz

then change a few phi and psi values of the pdb (so its slightly different from the native), run Calculate F (model)

model.mtz

Now I tried to calculate the CC of the two MTZ using Calculate Map Correlation.

I get the following:

"Missing at least one map file or label"

What am I doing wrong?

Thank you,

George