Having problems running DFTB using dftb.org parameter files on Gauss 09 (G09)?
First, at least for C.01, dftb=readparameters, in the route section, does not work dftb=read does but is not necessary.

Skip a line after molecular descritption and include your parameter files there. Make sure you include all pair interaction files, not just bonded atoms.  It should look something like this:

@C:/G09W/C-C_mio.skf
@C:/G09W/C-H_mio.skf
@C:/G09W/H-C_mio.skf
@C:/G09W/H-H_mio.skf

(I included the mio because we are running more than one parameter set, not a requirement just a name)

The real glitch comes from my final hint.  The DFTB parameters generally have more than 500 points, but the first line in the code is 500 (not 519, or 520, etc).  G09 Rev. D.01 doesn't care about this, B.01 and C.01 do.  You simply need to change 500 ro reflect the correct amount of points and add in the correct order for your atomic numbers (this part is explained on Gauss' website) and you are good to go.

Hopefully this helps anyone trying to run DFTB on G09 for the first time, and helps save some time.